S-modified hollow nanosheet MnO2/Ni(OH)2 for efficient urea oxidation electrocatalysis

S-modified MnO 2 /Ni(OH) 2 hollow nanosheets were constructed for enhanced UOR. • Requires 1.30 V at 10 mA cm −2 and remains stable for 48 h. • MnO 2 phase transformation promotes the generation of Ni 3+ active species. • S-modification enhances urea adsorption while suppressing competitive OH − adsorption. The urea oxidation reaction (UOR) provides an alternative anodic process for electrochemical hydrogen generation, but developing catalysts with high activity and sustained performance remains challenging. In this study, we report an S-modified nickel-based catalyst with a hollow nanosheet architecture (α/γ-MnO 2 /Ni(OH) 2 -S), demonstrating enhanced UOR performance in alkaline media. α/γ-MnO 2 /Ni(OH) 2 -S attains a current density of 10 mA cm −2 at a potential of 1.30 V and maintains reliable durability for 48 h without significant degradation. The improved activity and durability are associated with the hollow nanosheet structure, the phase transformation of MnO 2 , and S-modification, which facilitate mass transport and charge transfer, modulate the electronic structure of Ni(OH) 2 to promote the formation of Ni 3+ active species, and enhance the electrochemical response to urea at different concentrations. This research establishes a practical avenue for constructing advanced nickel-based UOR catalysts through rational structural optimization, phase regulation, and surface modification. Download: Download high-res image (125KB) Download: Download full-size image