Hydrogen spillover effect tuning the rate-determining step of hydrogen evolution over Pd/Ir hetero-metallene for industry-level current density

Despite the fruitful achievements in the development of high-performance catalysts, most of materials still suffer limited HER kinetics and poor durability in harsh acidic media, especially at high current densities. In this work, a Pd nanoparticles/Ir metallene heterojunction structure (Pd/Ir hetero-metallene) were successfully prepared by a facile co-reduction method. The hydrogen spillover bridging H+ adsorption/H2 desorption process occurring at the Pd/Ir interface results in the rate-determining step change to a Tafel step, which accelerates the HER kinetics. The Pd/Ir hetero-metallene has a relatively low ΔGHads (-0.19 eV), which allows for rapid adsorption of H+ and release of H2, thus greatly improving the performance of HER. As a result, the Pd/Ir hetero-metallene exhibits remarkable HER performance with ultra-low overpotentials of only 69 and 133 mV to reach 500 and 1000 mA cm−2, a small Tafel slope of 21 mV dec−1, and superb stability.