Coupling atom ensemble and electron transfer in PdCu for superior catalytic kinetics in hydrogen generation

The design of high-performance catalysts is the key to the efficient utilization of hydrogen energy. In this work, a PdCu nanoalloy was successfully anchored on TiO₂ encapsulated with carbon to construct a catalyst. Outstanding kinetics of the hydrolysis of ammonia borane (turnover frequency of 279 mol ${}_{{\mathrm{H}}_2}$∙min⁻¹∙mol_Pd⁻¹) ranking the third place among Pd-based catalysts was achieved in the absence of alkali. Both experimental research and theoretical calculations reveal a lower activation energy of the B–H bond on the PdCu nanoalloy catalyst than that on pristine Pd and a lower activation energy of the O–H bond than that on pristine Cu. The redistribution of d electron and the shift of the d-band center play a critical role in increasing the electron density of Pd and improving the catalytic performances of Pd_0.1Cu_0.9/TiO₂-porous carbon (Pd_0.1Cu_0.9/T-PC). This work provides novel insights into highly dual-active alloys and sheds light on the mechanism of dual-active sites in promoting borohydride hydrolysis.