Electronic modification of Ni active sites by W for selective benzylamine oxidation and concurrent hydrogen production

Abstract

We present self-supporting W-doped Ni2P nanosheet arrays, serving as bifunctional catalysts for selective electrooxidation of benzylamine (BA) to high-value benzonitrile (BN), while simultaneously promoting hydrogen production. The assembled W-Ni2P/NF||W-Ni2P/NF (NF: nickel foam) electrolyzer requires a voltage of only 1.41 V to achieve a current density of 10 mA cm−2 in alkaline solution containing 25 mmol L−1 BA, exhibiting an impressive Faradaic efficiency 95% for benzonitrile synthesis. In-situ Raman and FTIR spectroscopies identify catalytically active NiOOH centers and key catalytic intermediates. X-ray absorption spectroscopy (XAS) and theoretical calculations suggest that W acts as electron attractors on adjacent Ni atoms, forming an electron-deficient Ni domain that promotes the adsorption and activation of –NH2 group, leading to efficient dehydrogenation into C≡N bonds. The doped W also optimizes the adsorption of hydrogen (ΔGH*) on Ni2P, thus promote the hydrogen evolution. This work highlights the electronic modification of Ni active sites as a key factor for bifunctional electrocatalysis in selective nitrile electrosynthesis and concurrent hydrogen evolution.