Ni_<i>x</i>P_<i>y</i> Cocatalyst-Loaded MOF-Derived C/N–ZnO@B-Doped g-C₃N₄-Based Z-Scheme Nanohybrid: A Combinatorically Enhanced Ternary Photocatalyst towards Hydrogen Peroxide and Hydrogen Production

Abstract

In an alternative approach to mitigate the impending energy crisis, the photocatalytic production of H2O2 and H2 via semiconducting materials has currently attracted unprecedented research attention. In this study, NixPy nanoparticles modified with a ZIF-8 MOF-derived C/N–ZnO (CNZ)/B-doped g-C3N4 (BCN) nanohybrid were fabricated via a facile calcination-phosphidation strategy. Significantly, it was uncovered that NixPy acts as a robust visible-light-responsive cocatalyst that further promotes excitons’ antirecombination that are generated via the Z-scheme-based binary hybrid (CNZ/BCN). Hence, the photocatalyst ZIF-8-derived CNZ/BCN-NixPy exhibited intriguing results when subjected to photocatalytic H2O2 production (2873.46 μmol h–1g–1), which is approximately 2-fold higher than binary CNZ/BCN (1:1). Meanwhile, this optimized structure delivers an improved H2 evolution rate of 12,723 μmol h–1 g–1. The significantly enhanced photocatalytic efficacy of the ternary hybrid was mostly related to the intricate interfacial contact between the Z-scheme heterojunction constructed by CNZ and BCN, which was substantiated by different characterization techniques. Moreover, the artful integration of the NixPy cocatalyst into the binary hybrid further promoted the photogenerated charge separation and mobilization of photoexcitons and provides more surface reactive sites for photocatalytic reactions. Besides this, the synergistic effect of oxygen vacancies increases the transmission rate of photoexcitons and restrains the electron–hole recombination process. The enormously enhanced photocatalytic activity and better stability endowed a promising potential for the CNZ/BCN-NixPy composite towards photocatalytic applications. This research work not only sheds light on the substantial role of the NixPy cocatalyst in decreasing the dosages of noble metal cocatalysts for photocatalytic application but also reveals avenues to construct MOF-derived ternary heterostructures for photocatalytic energy conversion applications.