Interface Engineering of CoP₃/Ni₂P for Boosting the Wide pH Range Water-Splitting Activity

Abstract

Developing electrocatalysts with low price, high energy efficiency, and universal pH value for hydrogen/oxygen evolution reaction (HER and OER) is very important for the wide application of electrochemical water splitting in hydrogen production. The results of density functional theory show that the interface region of CoP3/Ni2P heterostructures can significantly boost all of the catalytic performances. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were used to confirm the abundant structural defects and the corresponding adjustment of the electronic state, thus ameliorating the activation energy, conductivity, and active area of the catalyst. Benefiting from these, CoP3/Ni2P heterostructures exhibit superior performance of both HER and OER in a wide pH range. CoP3/Ni2P can also be used for water splitting (1.557 V at 10 mA cm–2) more than 40 h, superior to benchmark pairs of Pt/C and RuO2 on Ni foam.

Charge-Storage Nickel Substrate-Boosted CuP2 Nanosheet for the Electrochemical Oxygen Evolution Reaction

“…This “nobler” nickel substrate enriches the surface oxidation state of CuP 2 /Ni, resulting in more charge accumulation in catalytic electrodes under an applied bias and thus accelerating the OER process. As a result, the CuP 2 /Ni-1 electrode could deliver current densities of 10 and 100 mA cm –2 at overpotentials of 260 and 324 mV (Figure S10), respectively, comparable to the recently reported state-of-the-art metal-phosphide-based heterojunction electrocatalysts ,− or self-standing electrodes − (Figure e and Table S3).…”

Heterostructure Interface Engineering in CoP/FeP/CeOx with a Tailored d-Band Center for Promising Overall Water Splitting Electrocatalysis

“…Tuning the ratio in bimetallic (Ni x Fe 1– x ) 2 P can lead to the regulation of the d-band energy level, and a moderate d-band center is key to balance the adsorption and desorption capacities toward intermediates . The strong atomic-level coupled interface region within the CoP 3 /Ni 2 P heterostructure can induce the leftward shift of the d-band center of Co, lower the energy barrier of OER with the reaction pathway changed, and optimize the Δ G *H , resulting in simultaneous enhancement of OER and HER catalytic activity . Other reports also disclosed the potential of heterogeneous bimetallic phosphides, such as Ni 2 P-Fe 2 P, Co 0.68 Fe 0.32 P-60, and Ru/FeCoP, for overall water splitting. − Notwithstanding these achievements, it remains a tremendous challenge to engineer interfaces into heterojunctional bimetallic phosphides with precise adjustment of the d-band center by multiple dimensional directions under simple synthetic conditions.…”

Boosting Synergy of Polymetal Phosphides by Core‐Shell Design of Prussian Blue Analogue Precursors as Electrocatalysts for Water Splitting

“…Transition metal phosphides, such as FeP, MoP and Ni 2 P have been investigated as either OER or HER electrocatalysts, which exhibit outstanding stability and good performance. [7][8][9][10][11][12] Doping other metal elements into single-metal phosphide can be an effective approach to further improve the electrocatalytic activity of catalysts. [13][14][15] For instance, Chai group fabricated Ni-Co bimetal phosphides, and Co substitution enhances the OER activity compared to Ni 2 P alone.…”