Electronic structure modulation and morphological engineering of trifunctional NixCoyP electrode for ultrastable overall water splitting at 1 A cm−2 and efficient biomass oxidation valorization

The development of transition metal electrocatalysts with excellent HER, OER and HMFOR activity can accelerate the achievement of “carbon peaking and carbon neutrality”. Herein, we report a simple structure modulation and morphological strategy for constructing Ni x Co y P-3 nanoneedles array with superhydrophilic/aerophobic surface. The small and well-dispersed nanoneedles can expose a larger electrochemical surface area. It has good mechanical stability, which can withstand the impact of violent bubbles at ampere-level current densities. Ni x Co y P-3 has a stronger H 2 O adsorption capacity than Ni 2 P, and can promote the adsorption and desorption of H* to facilitate the HER process. During the OER process, the formation of the Ni x Co y P-3/Ni x Co y OOH heterostructure is an important factor to stabilize oxygen evolution at ampere-level current densities. During the HMFOR process, Ni x Co y P-3 has a stronger HMF adsorption energy than Ni 2 P, and the generated FDCA can be desorbed from the Ni x Co y P-3 surface more easily. The overpotentials of the Ni x Co y P-3 are only 38.8 mV and 231.2 mV for HER and OER at 10 mA cm −2 in alkaline medium. When in the 1.0 M KOH + 50 mM HMF, only 1.37 V was required to reach a current density of 10 mA cm −2 of the Ni x Co y P-3 II Ni x Co y P-3 two-electrode system. Ni x Co y P-3 can drive 1000 mA cm −2 overall water splitting for 100 h of stable operation in 1 M KOH, validating its potential in industrial hydrogen production.