The photoelectrocatalytic urea oxidation reaction (PEC‐UOR) holds a great promise for the wastewater remediation and energy production. However, the low efficiency of semiconductor/cocatalysts type photoanodes for UOR restricts their applications in photoelectrocatalytic system. Herein, a new semiconductor/cocatalyst, Ni2P clusters sensitized TiO2 nanotube arrays photoanode (Ni2P/TiO2‐NTAs) for PEC‐UOR with high efficiency are developed. The 1D TiO2‐NTAs structure accelerates urea molecules diffusion and promotes CO2 gas release at the electrode interface. Meanwhile, Ni2P is also beneficial to urea molecule absorption and CO2 desorption and enable to lower the energy barrier for amine (NH) dehydrogenation. Furthermore, the robust interfacial charge transfer pathway between Ni2P and TiO2 interface promotes the separation of photogenerated electrons and holes and the transfer of photogenerated electrons from Ni2P to TiO2. Therefore, this photoanode shows excellent PEC‐UOR performance with the potential of 1.43 V versus reversible hydrogen electrode (RHE) when the current density reaches 10 mA cm−2, which is much lower than that of 2.24 V versus RHE and 1.58 V versus RHE for TiO2‐NTAs and Ni(OH)2/TiO2‐NTAs, respectively.
Photocatalysis and photoelectrocatalysis, as green and low-cost pollutant treatment technologies, have been widely used to simultaneously degrade pollutants and produce clean energy to solve the problems of environmental pollution and energy crisis. However, the disadvantages of photocatalysts in a narrow absorption range and low utilization rate of solar energy still hinder the practical application. Here we fabricate two-dimensional porous Ruddlensden–Popper type nickel-based perovskite oxide La2NiO4 as a noble metal-free photoanode for photoelectrocatalytic urea oxidation under full spectrum sunlight irradiation. The transient photocurrent density under near infrared (NIR) light (λ > 800 nm) can reach 50 μA cm−2. Urea wastewater was used as the fuel to obtain low-energy hydrogen production, and round-the-clock hydrogen production was achieved with the optimal yield of 22.76 μmol cm−2 h−1. Moreover, a photocatalytic urea fuel cell (PUFC) was constructed with La2NiO4 as the photoanode. The power density under UV-vis-NIR was 0.575 μW cm−2. Surprisingly, the filling factor (FF) under NIR light was 0.477, which was much higher than those under UV-vis-NIR and visible light. The results demonstrated that PUFCs constructed from low-cost nickel-based perovskite oxides have potential applications for low-energy hydrogen production and efficient utilization of sunlight.
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