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• Bimetallic nitride heterostructures is constructed to broaden the optical response. • The C@VN/TiN sample are synthesized by ammonia-assisted one-step calcination. • The C@VN/TiN sample has the best photoreduction CO 2 performance. There are still many challenges in inhibiting the recombination and differentiation of photogenerated carriers from promoting the conversion of CO 2 into hydrocarbons. Based on the functional differentiation of different metal sites, bimetallic nitride heterostructures is constructed to broaden the optical response and promote the separation of charge carriers in this work. Herein, carbon substrate-loaded double nitride heterostructure composites C@VN/TiN are synthesized by ammonia-assisted one-step calcination. In all samples, the C@VN/TiN-3 sample has the best photoreduction CO 2 performance with the promotion of lactic acid (LA) reagent. And the CH 4 yield of the C@VN/TiN-3 sample is 775 μmol g−1 h-1, which is 7.6 times and 10.3 times higher than C@VN (102 μmol g−1 h-1) and C@TiN (75 μmolg−1 h-1), respectively. The generation, separation, and migration of photogenerated electron-hole pairs are studied kinetically through transient photocurrent responses, electrochemical impedance spectroscopy and photoluminescence spectroscopy. The position and process of adsorption and activation of CO 2 and H 2 O are deduced by in situ characterization and reaction potential, and the determined possible path is explored by the peak of intermediates. This paper reveals the important roles of co-catalytic agents, ohmic junctions, and the function of bimetallic actives in enhancing photocatalytic activity, providing new ideas for constructing efficient photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrathin and single crystal of WO 3 nanoplates synthesized by a one-step hydrothermal technique. • This study shows a collaborative approach of facet engineering and p-n Junction of WO 3 /MoS 2 -MoO X. • Depth, surface, and interface of the WO 3 /MoS 2 -MoO X investigated by TOF-SIMS analysis. • The obtained WO 3 /MoS 2 -MoO X photoanode exhibits highly efficient and stable PEC H 2 generation. • H 2 and O 2 productions of the WO 3 /MoS 2 -MoO X after 2 h were 54.5 and 25.8 μmol cm−2, respectively. In this paper, we demonstrate a facet-controlled WO 3 nanoplate heterojunction with MoS 2 -MoO X nanosheets that produces extremely efficient and stable photoelectrochemical H 2 production. Furthermore, the effect of the hydrothermal process time (t = 1, 2, and 3 h) for the WO 3 photoanode and drop-casting process of the MoS 2 nanosheets (4, 8, and 12 times) to obtain the optimum amount of the material (MoS 2 and MoO X) for the PEC performance of the WO 3 /#n-MoS 2 and WO 3 /#n-MoS 2 -MoO X (n = 4, 8, and 12) photoanodes were investigated. The photocurrent density of the WO 3 /MoS 2 -MoO X photoanode was approximately 2.15 mA.cm −2 at 1.23 V vs. RHE, which was 8.6 and 1.2 times higher compare to pure WO 3 and WO 3 /MoS 2 photoelectrodes, respectively. The incident photon current efficiency of the WO 3 /MoS 2 -MoO X photoanode is approximately 27.5%, which is a significant improvement over that of bare WO 3. The WO 3 /MoS 2 -MoO X photoanode produced 54.5 μmolcm−2 of H 2 and 25.8 μmolcm−2 of O 2 after 2 h, at 1.23 V vs. RHE and 100 mWcm−2. The electrochemical kinetics clearly showed that water oxidation reaction was accelerated. The WO 3 /MoS 2 -MoO X photoanode, which was developed through simple and facial drop casting of MoS 2 nanosheets onto WO 3 photoanode, resulted in effective photogenerated carrier separation and enhanced oxygen evolution reactions on the anode surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrathin and single crystal of WO 3 nanoplates synthesized by a one-step hydrothermal technique. • This study shows a collaborative approach of facet engineering and p-n Junction of WO 3 /MoS 2 -MoO X. • Depth, surface, and interface of the WO 3 /MoS 2 -MoO X investigated by TOF-SIMS analysis. • The obtained WO 3 /MoS 2 -MoO X photoanode exhibits highly efficient and stable PEC H 2 generation. • H 2 and O 2 productions of the WO 3 /MoS 2 -MoO X after 2 h were 54.5 and 25.8 μmol cm−2, respectively. In this paper, we demonstrate a facet-controlled WO 3 nanoplate heterojunction with MoS 2 -MoO X nanosheets that produces extremely efficient and stable photoelectrochemical H 2 production. Furthermore, the effect of the hydrothermal process time (t = 1, 2, and 3 h) for the WO 3 photoanode and drop-casting process of the MoS 2 nanosheets (4, 8, and 12 times) to obtain the optimum amount of the material (MoS 2 and MoO X) for the PEC performance of the WO 3 /#n-MoS 2 and WO 3 /#n-MoS 2 -MoO X (n = 4, 8, and 12) photoanodes were investigated. The photocurrent density of the WO 3 /MoS 2 -MoO X photoanode was approximately 2.15 mA.cm −2 at 1.23 V vs. RHE, which was 8.6 and 1.2 times higher compare to pure WO 3 and WO 3 /MoS 2 photoelectrodes, respectively. The incident photon current efficiency of the WO 3 /MoS 2 -MoO X photoanode is approximately 27.5%, which is a significant improvement over that of bare WO 3. The WO 3 /MoS 2 -MoO X photoanode produced 54.5 μmolcm−2 of H 2 and 25.8 μmolcm−2 of O 2 after 2 h, at 1.23 V vs. RHE and 100 mWcm−2. The electrochemical kinetics clearly showed that water oxidation reaction was accelerated. The WO 3 /MoS 2 -MoO X photoanode, which was developed through simple and facial drop casting of MoS 2 nanosheets onto WO 3 photoanode, resulted in effective photogenerated carrier separation and enhanced oxygen evolution reactions on the anode surface. [ABSTRACT FROM AUTHOR]