Urea-assisted water splitting that includes hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) can produce high pure hydrogen and clean urea-rich wastewater, nonetheless the lack of effective design of highly active and economical multifunctional electrocatalysts hampers its application. Here, we introduce a novel hollow/porous NiP2/ZnP2/Sn nanoboxes by a facile precipitation method coupled with a simple ion exchange process and phosphorization step for the robust electrocatalytic HER and UOR processes. The specific porous hollow structure of NiP2/ZnP2/Sn boxes with large and abundant amount of edge active sites, improved electron/mass transportation, and modulated electronic structure offer superior electrocatalytic performance with bifunctional activities for both HER and UOR processes, with only 69 mV to achieve 10 mA cm−2 for HER and 60 mV to reach 10 mA cm−2 toward UOR with desirable long-term stability during 24 h. Moreover, the fabricated overall urea splitting systems based on NiP2/ZnP2/Sn as both cathode and anode electrodes, show very low cell voltages of 1.37 V to achieve 10 mA cm−2, making it one of the most efficient catalysts toward overall urea splitting. This effective strategy for fabricating hollow/porous metal-based boxes offers a new avenue for designing high performance catalysts in environmental and sustainable energy utilization.
