Photogenerated Carrier Mediated Dynamic Ni Site Engineering in NiCo LDH/Ni3S2 Heterostructures for Efficient Urea Oxidation

Abstract The anodic oxygen evolution reaction (OER) has sluggish kinetics and high energy consumption, while the urea oxidation reaction (UOR) is an ideal alternative anodic reaction due to its low theoretical potential (0.37 V vs RHE) and can also synergistically realize urea removal from wastewater and energy conversion. However, Ni-based catalysts often suffer from decreased activity and stability due to excessive Ni3+ accumulation, strong *COO adsorption, and competitive OER under high potentials. This work constructs a NiCo LDH/Ni3S2 heterostructured catalyst to improve UOR performance by regulating dynamic Ni sites via photogenerated carriers: the heterointerface enhances light absorption and carrier separation, and photogenerated holes promote Ni2+ oxidation to Ni3+ and strengthen urea adsorption, driving the Ni3+/Ni2+ dynamic cycle and inhibiting OER competition. The catalyst delivers a potential of 1.40 V vs RHE at 100 mA cm−2 with stable operation in photogenerated carrier-assisted UOR (PCAE-UOR) and reduces cell voltage in urea-assisted hydrogen production, supporting the design of PCAE-UOR catalysts with improved performance.