Dopant induced hollow Ni2P nanocrystals regulate dehydrogenation kinetics for highly efficient solar-driven hydrazine assisted H2 production
Umesh P. Suryawanshi, Uma V. Ghorpade, Priyank V. Kumar, Jun Sung Jang, Mingrui He, Hong Jae Shim, Hyo Rim Jung, Mahesh P. Suryawanshi, Jin Hyeok Kim
Abstract
Replacing kinetically sluggish oxygen evolution reaction (OER) with a thermodynamically favorable hydrazine oxidation reaction (HzOR) to produce hydrogen has emerged as a more energy-efficient alternative than water splitting. However, the lack of promising bifunctional electrocatalysts hinders its scalable applications. Here, we report a colloidal synthesis of Mn-dopant induced hollow Ni2P nanocrystals (NCs) using a heat-up approach, which act as superior bifunctional electrocatalysts for both HzOR (55 mV at 10 mA/cm2) and hydrogen evolution reaction (HER, 192 mV at 50 mA/cm2). The two-electrode electrolyzer requires a low cell voltage of 59 mV to achieve 10 mA/cm2 and a current density of ~ 50.4 mA/cm2 to reach 0.5 V. Theoretical studies unraveled that Mn-doping regulates the electronic structure of Ni2P and optimizes the H* adsorption/desorption and dehydrogenation kinetics. When integrated with a Si photovoltaic device, the bifunctional hollow Mn-doped Ni2P NCs enabled solar-driven hydrazine assisted H2 production with a ~ 14.6% efficiency.