Regulating the intermediate affinity on Pd nanoparticles through the control of inserted-B atoms for alkaline hydrogen evolution

Strong affinity of palladium to hydrogen needs to be overcome in the rational design of highly efficient and robust Pd-based catalyst for hydrogen evolution reaction (HER). In this work, we achieved the insertion of boron atoms in the Pd lattice interstitial sites by a facile co-reduction method, and successfully prepared Pd-B nanoparticles supported on carbon. Benefiting from the optimization of electronic state induced by the control of interstitial boron atoms, the obtained Pd86B14/C catalyst exhibit pronounced alkaline HER performance with a small overpotential of 38 mV at 10 mA cm−2 and a low Tafel slope of 36.6 mV dec−1 in 1 M KOH. Theoretical calculations unveil that the inserted boron atoms into host palladium leads to the charge redistribution and the lower d-band center on Pd because of the electron transfer between Pd and inserted B. More importantly, the control of inserted boron atoms makes the d-band center of Pd appropriately shift negatively relative to the Fermi level and consequently balances the hydrogen adsorption/desorption behavior of Pd surface, resulting in superior catalytic performance (Pd86B14/C).