Ni3(PO4)2 with Pt nanoparticles in-situ decoration: a superior self-powered hydrogen production trifunctional catalyst

Hydrogen produced through self-powered water-splitting can effectively meet the demand for miniaturized devices. However, the design of an efficient catalyst that integrates a zinc-air battery (ZAB) with a water-splitting cell is crucial for the development of such devices. In this study, we synthesized Pt/Ni 3 (PO 4 ) 2 on nickel foam (NF) via a two-step process. The resulting Pt/Ni 3 (PO 4 ) 2 /NF exhibited significantly enhanced trifunctional properties (hydrogen evolution reaction, HER; oxygen evolution reaction, OER; oxygen reduction reaction, ORR) compared to the Ni 3 (PO 4 ) 2 /NF precursor. Additionally, the ZAB assembled using Pt/Ni 3 (PO 4 ) 2 /NF as the air-cathode demonstrated superior rechargeable performance compared to the Ni 3 (PO 4 ) 2 /NF-based counterpart. Moreover, when Pt/Ni 3 (PO 4 ) 2 /NF was directly used as both the cathode/anode for the water-splitting device and the air-cathode for the ZAB, the self-powered hydrolysis device exhibited excellent hydrogen production performance. Upon investigating the influence of in-situ decorated Pt nanoparticles, we found that these Pt nanoparticles: 1) facilitate the morphological reconstruction of Ni 3 (PO 4 ) 2 , thus increasing the electrochemical surface area of the catalyst; 2) lower the hydrogen adsorption free energy of Pt/Ni 3 (PO 4 ) 2 , and the associated OER theorical potential; 3) shift the d-band center of Pt/Ni 3 (PO 4 ) 2 closer to the Fermi level, ultimately enhancing its intrinsic catalytic activity. This work is expected to provide a foundation for experimental, theoretical, and practical applications of other Ni 3 (PO 4 ) 2 -based multifunctional materials.