Metal–Organic Framework (MOF)-Derived Electron-Transfer Enhanced Homogeneous PdO-Rich Co3O4 as a Highly Efficient Bifunctional Catalyst for Sodium Borohydride Hydrolysis and 4-Nitrophenol Reduction

Developing a bifunctional catalyst with low cost and high catalytic performance in NaBH₄ hydrolysis for H₂ generation and selective reduction of nitroaromatics will make a significant impact in the field of sustainable energy and water purification. Herein, a low-loading homogeneously dispersed Pd oxide-rich Co₃O₄ polyhedral catalyst (PdO-Co₃O₄) with concave structure is reported by using a metal–organic framework (MOF)-templated synthesis method. The results show that the PdO-Co₃O₄ catalyst has an exceptional turnover frequency (3325.6 mol_H2 min^?1 mol_Pd^?1), low activation energy (43.2 kJ mol^?1), and reasonable reusability in catalytic H₂ generation from NaBH₄ hydrolysis. Moreover, the optimized catalyst also shows excellent catalytic performance in the NaBH₄ selective reduction of 4-nitrophenol to 4-aminiphenol with a high first-order reaction rate of approximately 1.31 min^?1. These excellent catalytic properties are mainly ascribed to the porous concave structure, monodispersed Pd oxide, as well as the unique synergy between PdO and Co₃O₄ species, which result in a large specific surface area, high conductivity, and fast solute transport and gas emissions.