In situ constructing atomic interface in ruthenium-based amorphous hybrid-structure towards solar hydrogen evolution

Synthesis and structural characterization

The designing of the photocatalytic H₂ evolution system was schematically illustrated in Fig. 1. Through the strategy of in-situ oxygen impregnation, we homogeneously integrated the amorphous Ru and RuO_x species into a hybrid-nanoparticle at the atomic scale, and thus creating multiple heterointerfaces. The amorphous RuO_x sites generated in situ were designed for hole trapping, while the amorphous Ru sites were designed as the electron acceptor for catalytic reaction. As such, compared with the traditional heterojunction with single heterointerface and few contact surfaces, the photogenerated electrons and holes from g-C₃N₄ support can be effectively separated, and the reduction/oxidation reactions can be decoupled spatially, on such atomically homogeneous Ru-RuO_x amorphous hybrid-structure. The preparation of amorphous Ru and Ru-RuO_x nanoparticles anchored on g-C₃N₄, named RCN and RRCN, respectively, was represented in Fig. 2a (for details see “Methods”). Starting from bulk g-C₃N₄ obtained by thermal polymerization of urea, the RCN photocatalyst was synthesized by calcinating ruthenium carbonyl (Ru₃(CO)₁₂) which was fully adsorbed on ultra-thin g-C₃N₄ nanosheets (Supplementary Fig. 1). Subsequently with a partial oxidation process, the RRCN as a H₂ evolution photocatalyst was successfully constructed. The Ru content for RCN and RRCN was determined to be ~1.5 wt% according to the inductively coupled plasma optical emission spectrometry (ICP-OES) analysis.

The alternative text for this image may have been generated using AI.

Schematic illustration of the solar-driven H₂ evolution system on Ru-RuO_x/C₃N₄ with multiple and single hetero-interface.

The alternative text for this image may have been generated using AI.

a Schematic illustration of the preparation strategy for RCN and RRCN. b–e HAADF-STEM, SEAD (inset), and high-resolution AC-HAADF-STEM images of RCN (b, c) and RRCN (d, e), respectively. f AC-HAADF-STEM image and near atomic resolution mappings of RRCN. g k²-weighted Fourier transform (FT) Ru K-edge EXAFS spectra for RCN, RRCN and Ru foil and RuO₂ (no phase correction).

In order to examine the morphology and structure of Ru species in the photocatalysts, transmission electron microscopy (TEM) was first carried out. As shown in Fig. 2b and Supplementary Fig. 2, the Ru nanoparticles in the RCN sample with an average diameter of 3.8 nm were uniformly dispersed on the g-C₃N₄ nanosheets (CN). As shown in the Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) image and high-resolution transmission electron microscopy (HRTEM) image (Fig. 2c and Supplementary Fig. 2), the Ru nanoparticles exhibit the disordered atomic structure, confirming the amorphous feature. Similarly, the dispersive morphology and amorphous nature remained unchanged for the partially oxidized Ru-RuO_x nanoparticles, except that the average particle diameter increased to 4.4 nm (Fig. 2d, e and Supplementary Fig. 3) which is possibly resulted from the impregnation of oxygen atoms into the amorphous Ru particles. In addition, energy-dispersive X-ray spectroscopic (EDS) mapping analysis revealed the homogeneous dispersion of Ru species in the RRCN and RCN samples (Supplementary Figs. 4 and 5). It is noteworthy that, compared to RCN, the EDS mapping distribution of the oxygen element in RRCN was well consistent with Ru nanoparticles, thus manifesting the formation of RuO_x component. Besides, the near atomic resolution mapping of the RRCN sample in Fig. 2f showed that the O atoms were randomly distributed in the amorphous Ru-RuO_x hybrid-particle, which indicated that the hybrid-particles existed in the form of multi-Ru-RuO_x heterointerface rather than core-shell structure³¹. Furthermore, selected area electron diffraction (SEAD) and X-ray powder diffraction (XRD) tests were conducted to further confirm the amorphous feature of Ru species in RCN and RRCN. As shown in the SEAD patterns (the inserts in Fig. 2b, d), no diffraction spot or diffraction ring of Ru/RuO₂ can be found except the only diffraction ring indexed to the (002) crystal plane of CN³². Meanwhile, neither Ru nor RuO₂ diffraction peak were observed in the XRD patterns (Supplementary Fig. 6). However, once RuCl₃ was served as the metal precursor instead of Ru₃(CO)₁₂, both Ru and Ru-RuO_x particles existed as crystalline structure under the same synthetic procedure (Supplementary Figs. 7 and 8). This is likely due to that the Ru³⁺ ions adsorbed on the support are prone to migration, nucleation, and growth during the annealing process lacking of intermolecular interaction, which led to the formation of nanocrystalline Ru particles.

To further identify the local structures of the nanoparticles, we performed synchrotron radiation X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) tests at the Ru K-edge. As shown in the XANES spectra (Supplementary Fig. 9), compared with Ru foil, the absorption edges of RRCN shifted to the higher energy side, along with an increase of the white line-peak intensity, meaning that the oxidation states of Ru increased^33,34 which was attributed to the generation of RuO_x. Furthermore, Fig. 2g shows the corresponding Fourier transformed k²-weighted EXAFS spectra for RCN and RRCN. Two dominant peaks of the RRCN sample at approximate 1.56 Å and 2.40 Å can be assigned to the Ru-O and Ru-Ru coordination³⁵, suggesting the formation of RuO_x species due to the impregnation of oxygen atoms into Ru nanoparticles. Besides, the position of Ru-O coordination peak in RRCN is slightly positive than that in RuO₂ (1.53 Å), which demonstrated the volume expansion of amorphous Ru-RuO_x particles compared to the crystalline RuO₂ and was in good agreement with the above electron microscopy results.

In situ tracking the controlled oxygen impregnation process

To further understand the existence states of Ru and RuO_x species and their dynamic evolutions during the oxygen insertion process, X-ray photoelectron spectroscopy (XPS) depth profiling with ion beam etching was carried out first. The RRCN sample was deposited on silicon wafer and treated with argon ion beam sputtering which can remove 10 nm surface samples per minute. As shown in the XPS spectra of Ru 3d orbital (Fig. 3a), the peak located at 281.03 eV in the pristine RRCN sample can be assigned to the Ru 3d_5/2 state of oxidated Ru^δ+. With the sputtering depth increased to ~1.7 nm gradually, the Ru 3d_5/2 peak shifted to 280.55 eV, suggesting the decreasing of the oxidation state of Ru³⁶. In addition, as the oxygen impregnation depth increases, the resistance goes higher, resulting in the higher oxidation state of Ru on the surface of the hybrid Ru-RuO_x nanoparticles than that in the interior. According to the XPS depth profiling, the inset in Fig. 3a illustrated the existence state of Ru-RuO_x nanoparticles in the RRCN sample, in which the Ru and RuO_x clusters are randomly distributed to form the uniquely homogeneous heterostructures. Different from the separated Ru and RuO₂ nanoparticles, a large number of Ru/RuO_x heterointerfaces in RRCN could enable the rapid separation/slow recombination of the photoexcited carriers and participation in chemical reactions, thus promoted the photocatalytic H₂ evolution.

The alternative text for this image may have been generated using AI.

a High-resolution XPS spectra at different sputtering depths for Ru 3d of the RRCN sample. b In-situ XANES spectra recorded at the Ru K-edge of RRCN at different oxidation time during the heat process, and the XANES data of the referenced standards of Ru foil and RuO₂. Inset, Magnified absorption edge and white-line peak of XANES region. c Least-squares curve-fitting analysis of in-situ EXAFS spectra at the Ru K-edge. Inset, In-situ XANES spectra recorded at the Ru K-edge of RRCN at different oxidation time during the heat process. d Schematic illustration of the oxygen insertion process during the formation of RRCN. e Wavelet analysis of the RRCN sample during in-situ EXAFS states.

Accompanied by the evolution of local geometric structure, the composition and electronic structural changes of the nanoparticles during the partial oxidation process can be revealed by the in situ XAFS results at the Ru K-edge. The in situ XAFS experiment was conducted in a homemade cell under an air atmosphere of 200 °C. Beginning with the RCN sample, a series of XAFS spectra were collected in different oxidation time (T_t, t = 0, 10, 20, 30, 50, 100 min). The XANES results in Fig. 3b showed that as the oxidation time increased, the absorption edge slightly shifted to the higher energy position, indicating the increase of Ru oxidation state due to the insertion of oxygen atoms. As reflected by the absorption edges of XANES spectra for Ru foil and RuO₂ standards, the Ru valence states in all of the samples lie between 0 and +4 (Fig. 3b and Supplementary Fig. 10). In addition, after comparing with the Ru foil and RuO₂ references, we can find the sequential evolution of the white line peaks of the RRCN-T_t spectra, implying that the oxygen is inserted into the Ru nanoparticles to form RuO_x.

Next, the local structural evolution of the atomically homogeneous Ru-RuO_x amorphous hybrid-nanoparticles was identified by EXAFS. Figure 3c exhibited the typical Fourier transformed (FT) k²-weighted EXAFS spectra for different oxidation times, together with the referenced samples (Supplementary Fig. 11). With respect to the T₀ spectrum, the dominant peak at approximately 2.43 Å can be assigned to the metallic Ru-Ru coordination. As the high-temperature oxidation process started, a fresh peak at approximately 1.61 Å (T₁₀) appeared which can be assigned to the Ru-O coordination. As the reaction time increased, the intensity of Ru-Ru peak at 2.43 Å gradually decreased, accomplished by the increase of the Ru-O coordination peak. This result implies that the Ru nanoparticles transforms into Ru-RuO_x by degrees, which well coincides with the XANES results. Figure 3d illustrated the oxygen impregnation process during the formation of RRCN. With the continuous oxygen impregnation, the position of Ru-O coordination peak shortened to ~1.55 Å. Quantitative structure information can be obtained by least-squares EXAFS curve-fitting analysis (Fig. 3d and Supplementary Table 1), and the corresponding Re(k²χ(k)) oscillation and fitting curves are exhibited in Supplementary Figs. 12 and 13. For the T₀ curve, the best fitting result showed coordination number (CN) of 6.6 for Ru-Ru, lower than that of Ru foil which is 12. This strongly suggested that the Ru nanoparticles existed in a small size and amorphous state, resulted in high surface atomic ratio and a large number of unsaturated coordination sites. Interestingly, the CNs of Ru-Ru and Ru-O gradually decreased from 6.6 to 3.1 and increased from 0 to 3.4, respectively, along with the continuous impregnation of oxygen atoms, reflecting that the amount of RuO_x component in the homogeneous Ru-RuO_x heterostructures can be well tuned. In addition, the controlled experiments of RRCN-cry-T_t (t = 30, 50, 100) samples were conducted under the same condition (Supplementary Fig. 14). It can be found that the crystalline Ru particles transformed into RuO_x immediately as the high-temperature oxidation process initiated, validating that the amorphous nanoparticles had much higher stability than the crystalline ones.

The wavelet transform (WT) of EXAFS in k-space was employed to confirm the coordination information on the Ru site. The WT contour plots with optimum resolution were drawn based on the Morlet wavelet. The WT analysis of RRCN-T_t spectra showed two prominent maximum values at 4.8 Å⁻¹ and 8.9 Å⁻¹ (Fig. 3e and Supplementary Fig. 15), which are assigned to the Ru-O and Ru-Ru scattering paths³⁷. Similar to EXAFS results, the bond length of Ru-O shortened, and the scattering intensity of Ru-O increased little by little. These detailed WT-EXAFS analyses and the in-situ XAFS characterizations shed light on the dynamic oxygen insertion process in the formation of hybrid Ru-RuO_x nanoparticles, which is potentially conductive to the atomic-precisely design and synthesis of photo/electrocatalyst.

Optical and semiconductor properties

The ultraviolet-visible diffuse reflectance spectra (DRS) were performed to verify the optical properties of the synthesized RCN and RRCN samples. As shown in the UV-vis DRS of the RCN and RRCN samples (Fig. 4a), they inherited the photophysical features of C₃N₄. All the samples display similar bandgap (nearly 2.96 eV, inset in Fig. 4a) and strong absorption in the range below 435 nm dominated by the C₃N₄ nanosheets, indicating their similar light absorption behavior³⁸. Notably, the RCN and RRCN samples showed a strong and broadband enhanced absorption tail from 440 nm to 800 nm compared with pristine C₃N₄. This feature cannot arise from scattering and can be attributed to the interband transition in Ru/RuO_x nanoparticles, which is in agreement with the color change of samples from bright yellow (C₃N₄) to dark blue (RCN) and gray blue (RRCN) (Supplementary Fig. 16).

The alternative text for this image may have been generated using AI.

a UV-vis diffuse reflectance spectroscopy of CN, RCN, and RRCN. Insert, Tauc plot of the diffuse reflectance data in (a). b Steady-state PL spectra at 298 K. c Time-resolved PL kinetics at the corresponding steady-state emission peaks in (c) at 298 K. d TA spectra of RRCN probed at the indicated time delays following excitation by a 350 nm pulse. e TA kinetics probed at the XB center (∼500 nm; open symbols). f Physical picture of charge transfer.

To further investigate the efficient electron-hole separation between the Ru-RuO_x nanoparticles and C₃N₄ support, the steady-state PL measurements were employed upon excitation with 350 nm light. The PL peaks of all samples were at ~456 nm, corresponding to a Stokes shift of ~0.1 eV of C₃N₄. As shown in Fig. 4b, the PL quenching efficiency increased from ~51.2% for RCN to ~72.1% for RRCN, reflecting the electron and sequential hole transfer to the Ru/RuO_x component on the basis of the schematic energy level alignment³⁹. Moreover, time-resolved PL spectra recorded at the corresponding steady-state emission peaks were also performed (Fig. 4c). Compared with C₃N₄ nanosheet, the decay of PL features was accelerated for the RCN and RRCN samples, which could be attributed to the amorphous Ru nanostructure and atomically homogeneous Ru-RuO_x amorphous hybrid-structure with multi-heterointerfaces. By fitting the PL kinetics in Fig. 4c, we extracted the averaged lifetime of 1.71 ± 0.18 ns, 1.07 ± 0.14 ns, 0.62 ± 0.1 ns for free C₃N₄, RCN, and RRCN, respectively, which was also consistent with the static PL spectra and further confirmed the charge transfer from photoexcited C₃N₄ to the amorphous nanoparticles. In order to reveal the charge transfer of the as-synthesized photocatalysts, ultrafast TA spectroscopy with a femtosecond pump-probe configuration was carried out. Briefly, a pump pulse at 350 nm was used to selectively pump the C₃N₄, and the induced absorption changes were monitored by a white light continuum probe pulse, which provides a complete record of electron transfer, hole trapping, and recombination events. Figure 4d showed the typical TA spectra of the RRCN sample at indicated delays. The spectral features are dominantly contributed by C₃N₄, including an exciton bleach (XB) feature at ∼475 nm. The XB feature can be assigned to state-filling-induced bleach by photogenerated excitons (CB electrons and VB holes)^40,41.

To further unveil the excited state dynamics of these photocatalysts, their TA kinetics of XB at 500 nm were compared. Notably, the decay tendency of the XB and the time-resolved PL (Fig. 4c) were in excellent agreement with each other for the CN, RCN, and RRCN samples. Considering that the charge transfer process almost accomplished within 15 ps for the RRCN and RCN samples, all the kinetics traces can be fitted (Fig. 4e and Supplementary Fig. 17) in this timescale. The decay of XB kinetics for the free C₃N₄ sample can be well-fitted using a mono-exponential decay function, resulting from the inherent photogenerated charge recombination. Compared to the free C₃N₄ sample, the fitting result of the RCN sample showed an electron transfer process with a time constant of 1.73 ps, owning to the electron transfer of C₃N₄ to amorphous Ru nanoparticles. Moreover, the RRCN sample possessed an additional channel for charge transfer. Due to the hole transfer ability of ruthenium-based molecules or ruthenium oxide¹² and the instrument response function (IRF) of the TA setup (~100 fs), it is strongly suggested that the hole capturing time from the VB of C₃N₄ to amorphous RuO_x component is <100 fs. Such femtosecond hole capturing and the picosecond electron transfer enable an extremely long-lived charge-separated states (recombination between an electron in the Ru site and a hole captured by the RuO_x site), exceeding the time window of 8 ns for TA test (Fig. 4e and Supplementary Fig. 17). On the basis of the UPS (Supplementary Fig. 18), TA and time-resolved PL spectroscopy results, a unified physical picture for the charger transfer models of the RRCN sample is summarized in Fig. 4f and Supplementary Fig. 19. Under irradiation light, taking the advantage of amorphous structure and atomically homogeneous multi-heterointerfaces, the amorphous RuO_x component traps the photogenerated hole in an ultrafast process of <100 fs and the amorphous Ru site enables an ultrafast electron transfer process of 1.73 ps. As a result, a long-lived charge-separated state is formed, which is long due to the reduced electron-hole wave function overlap. It is beneficial to the efficient accumulation of the transferred electrons into Ru site, possibly accounting for the significantly improved photocatalytic activity. Due to its efficient charge transfer and fast switching of reactive species, this special atomically homogeneous Ru-RuO_x hybrid-structure with multiple heterointerfaces will play an important role in photo/electrocatalytic applications.

Evaluation of photocatalytic performance

The photocatalytic H₂ evolution performance of the as-obtained catalysts was evaluated in a closed cylinder Pyrex glass container (for details see “Methods”). The photocatalytic experiment of the RCN sample was conducted in neutral water in the presence of TEOA (15 vol%) as sacrificial reagent under simulated solar illumination conditions (AM 1.5G filter), while that of the RRCN sample was conducted without any sacrificial reagents. Figure 5a illustrated the typical H₂ evolution rate of the RCN and RRCN samples, respectively. Compared with the pristine C₃N₄ (1.8 μmol·h⁻¹) which had poor photocatalytic efficiency, the H₂ evolution rate of amorphous Ru nanoparticles modified RCN remarkably increased to 380.2 μmol·h⁻¹, ~200-fold higher than that of pristine C₃N₄. In addition, under the condition of pure water without any sacrificial reagents, co-catalysts, or other additives, the optimized oxygen inserted RRCN sample exhibited exciting performance with the H₂ evolution rate up to 60.8 μmol·h⁻¹. On the basis of the photocatalytic tests, we deduced that Ru component in Ru-RuO_x served as the active sites for H₂ evolution, while the RuO_x worked as the hole trapping agent. Besides, the controlled experiments which modified Ru nanocrystalline particles were also performed under the same condition. As shown in Fig. 5b, the RCN and RRCN samples modified by amorphous Ru nanoparticles exhibited better photocatalytic activities than the Ru nanocrystalline modified RCN-cry and RRCN-cry samples, with 1.5 and 3.2-fold higher H₂-evolution rates, respectively. Distinctive from Ru nanocrystals with lattice periodicity, the specific disordered atomic structure of amorphous Ru nanoparticles endowed them with highly chemical homogeneity, abundant defects, and unsaturated coordination sites, thus achieving better photocatalytic H₂ evolution activity.

The alternative text for this image may have been generated using AI.

a Typical time course of H₂ productions under light irradiation (λ ≥ 350 nm) for CN, RCN (left, with 15 vol % TEOA as sacrificial agent), and RRCN (right, without sacrificial agent). b Comparative presentation of the H₂ evolution rates. c Photocatalytic H₂ evolution activities under simulated sunlight (λ ≥ 350 nm) and visible (λ ≥ 400 nm) light irradiation. d AQYs and H₂ evolution rates of RCN and RRCN under irradiation with light of different wavelengths. e I–t curves of various catalysts with and without light at 0.3 V (vs. Ag/AgCl). f H₂ productions and the furfuryl alcohol oxidation to furfural performance for the RRCN sample.

Considering the limitation of C₃N₄ semiconductor on near ultraviolet light and the demand for the use of visible light in the development of new energy, we also evaluated the performance of the designed RCN and RRCN catalysts under visible light (λ ≥ 400 nm). As exhibited in Fig. 5c, in the visible range, the wide band gap leaded to a decrease of photogenerated excitons, resulting in a sharply drop in the H₂ evolution rate of RCN and RRCN to 146.2 μmol·h⁻¹ and 22.4 μmol·h⁻¹, respectively. Figure 5d and Supplementary Fig. 20 showed the wavelength-dependent apparent quantum yields (AQYs) and H₂ evolution rate of RCN and RRCN under irradiation light. Specifically, the obtained RRCN achieved a 7.4% quantum efficiency at 380 nm, 3.1% at 400 nm, and 0.8% at 420 nm. Unfortunately, the H₂ evolution rate of the RRCN and RCN samples in the visible light range is significantly reduced due to the weak absorption of g-C₃N₄ support to visible light⁴². Despite of the relatively reduced performance in the visible light range, our current work provides a very promising system based on the atomically homogeneous Ru-RuO_x amorphous hybrid-structure for the separation and utilizing of photogenerated carriers. If the band structure of light-absorbing centers could be tuned to further improve the photoresponse, higher AQYs performance would be achieved under visible light.

To further investigate the charge separation characters of the photocatalysts under working condition, photoelectrochemical (PEC) tests were performed. As shown in Fig. 5e, the photocurrent-time curves indicated that the photocurrents were enhanced for the RCN and RRCN samples compared to the pristine C₃N₄, proving that the loading of amorphous Ru and Ru-RuO_x nanoparticles boosts the separation of photoexcited e⁻–h⁺ pairs. The construction of the amorphous Ru/Ru-RuO_x nanoparticles and C₃N₄ can accelerate the carriers transporting from C₃N₄ support to the nanoparticles to participate in the redox reaction. Moreover, according to the electrochemical impedance spectroscopy (EIS) (Supplementary Fig. 21), compared with the light off condition, all of the RCN, RRCN and pristine C₃N₄ samples possessed smaller radii under light irradiation. The RRCN sample displayed the smallest radius than that of the RCN and pristine C₃N₄ samples, demonstrating the lowest charge-transfer resistance and thus achieved efficient charge separation⁴³, which was highly consistent with the above photocatalytic and spectroscopy results.

In order to investigate the stability and underlying reaction mechanism of RRCN catalysts, we performed recycling experiments and characterized the samples after the reaction. As shown in Supplementary Fig. 22, the RRCN sample can stably produce H₂ at the beginning of the reaction, but it is rapidly inactivated after a period of time. The morphology of the RRCN catalyst shown in Supplementary Fig. 23 exhibits a similar amorphous structure to the pristine one. While as can be seen from the XPS results of Ru 3d orbits (Supplementary Fig. 24), the valence state of Ru after the hydrogen evolution reaction (RRCN-AR) increases significantly which might be due to the hole oxidation of Ru⁰ and the lower value Ru^α+O_x species to the higher value Ru^δ+ in the H₂ evolution reaction. Similar results can be seen in the XANES and EXAFS spectra in Supplementary Fig. 25, the absorption edge and white line peak of RRCN-AR sample were significantly shifted to the right and up, respectively, and the Ru-Ru scattering peaks in R space almost disappeared, indicating that the valence state of Ru in RRCN increased significantly. Consequently, we suspect that at the beginning of the catalytic reaction, both the Ru⁰ component and Ru^α+O_x component exist in the RRCN sample, and the Ru⁰ component is used as hydrogen evolution sites to reduce protons to produce hydrogen, and the Ru^α+O_x component with lower value Ru^α+ captures and consumes holes due to the variable valence state of Ru^δ+ (+2, +3, +4, +6), and its own oxidation occurs. When the reaction time is prolonged, the Ru species and the functional groups such as -NH₂ in g-C₃N₄ carrier are oxidized, the ability of Ru^δ+O_x with higher value Ru^δ+ consuming holes is greatly reduced, so that the H₂ evolution of the whole system cannot be realized. To further highlight the effectiveness of our designed RRCN catalyst with multi-heterointerfaces, we applied it to the photocatalytic H₂ evolution and furfuryl alcohol oxidation coupling system. The results in Fig. 5f and Supplementary Fig. 26 showed that the RRCN catalyst exhibited high activity with a H₂ evolution rate of 84.8 μmol·h⁻¹. Meanwhile, the recycling experiment in Supplementary Fig. 27 conducted that the furfuryl alcohol consumed photoexcited holes in time, which greatly enhanced the stability of the system. Moreover, both the XPS and XAFS results in Supplementary Figs. 24 and 25 indicated that the valence state of Ru rarely changed during the stability test, heralding multi-heterointerfaces system as candidates for artificial photosynthesis.

In summary, compared with the traditional photocatalytic H₂ evolution catalysts that require hole sacrificial agents or reaction sites, we have developed a novel strategy to in-situ construct an integrated photocatalyst composed of atomically homogeneous Ru-RuO_x amorphous hybrid-structure with multi-heterointerfaces supported on g-C₃N₄ nanosheet which could achieve femtosecond hole trapping, therefore, exhibited exceptional activity for efficient solar-driven H₂ evolution and artificial photosynthesis. Our study demonstrated that under irradiation light, the amorphous RuO_x and Ru sites can instantly trap the photogenerated holes and enable an efficient electron transfer, respectively, thus resulting in an extremely long-lived charge-separated state for reaction. Besides, combined the oxygen impregnation strategy, for the first time, we identified the entry and diffusion of oxygen in the formation of Ru-RuO_x hybrid-structure at the atomic scale by in-situ XAFS technique. These findings not only provide an efficient artificial photosynthesis system based on the amorphous Ru-RuO_x hybrid-structure with the ultrafast hole trapping ability, but also unravel the essential structural evolution that can guide the rational design of amorphous heterogeneous catalysts.