Electrocatalytic Activity and Stability Enhancement through Preferential Deposition of Phosphide on Carbide

Abstract

Phosphides and carbides are among the most promising families of materials based on earth‐abundant elements for renewable energy conversion and storage technologies such as electrochemical water splitting, batteries, and capacitors. Nickel phosphide and molybdenum carbide in particular have been extensively investigated for electrochemical water splitting. However, a composite of the two compounds has not been explored. Here, we demonstrate preferential deposition of nickel phosphide on molybdenum carbide in the presence of carbon by using a hydrothermal synthesis method. We employ the hydrogen evolution reaction in acid and base to analyze the catalytic activity of phosphide‐deposited carbide. The composite material also shows superior electrochemical stability in comparison to unsupported phosphide. We anticipate that the enhanced electrochemical activity and stability of carbide deposited with phosphide will stimulate investigations into the preparation of other carbide–phosphide composite materials.

Structural Design and Electronic Modulation of Transition‐Metal‐Carbide Electrocatalysts toward Efficient Hydrogen Evolution

“…The synergy between two active phases can be ascribed to the electron transfer through heterointerfaces, which optimizes electronic configuration toward promoted activity and stability. Wang developed Ravenala ‐leaf‐like W x C@WS 2 as an efficient electrocatalyst via carbonizing WS 2 nanotubes ( Figure a) .…”

“…In the further investigation on W 2 C‐WN, XANES analysis confirmed downshifting of W ε d in the presence of nitride compared with W 2 C, leading to the enhanced HER activity. Regmi et al attested the electronic interactions on Ni 2 P–Mo 2 C interfaces that caused the visible blueshift in Mo 3d and thus the enhanced HER activity . Zhao et al conducted further control on Mo–S–C sites in vertically aligned MoS 2 /Mo 2 C nanosheets via controlled carbonization of MoS 2 precursors, resulting in a low η 10 of only 63 mV in 0.5 m H 2 SO 4 .…”

“…Other efforts have been devoted to build other active phases on TMC surface. For example, Regmi et al investigated the deposition of transition‐metal phosphide (FeP, CoP, and Ni 2 P) nanoparticles onto Mo 2 C nanoparticles via solvothermal decomposition . The electrocatalytic tests in 0.5 m H 2 SO 4 showed the high HER activity comparable to those of state‐of‐the‐art non‐noble metal catalysts.…”

Lattice Matched Carbide–Phosphide Composites with Superior Electrocatalytic Activity and Stability

“…Mo2C templated on MWCNT was synthesized using a recently reported ball-milling and carbothermic reduction method. 29 In brief, a 20:1 mass ratio of ball to a mixture of MoO3 and MWCNT was ball-milled for 20 hours at 300 rpm followed by carbothermic reduction under Ar atmosphere at 950 ºC. The ramping rate was 1 ºC min -1 , the Ar flow rate was 0.5 L min -1 , and the tube furnace was allowed to cool naturally to ambient temperature without any dwell time at 950 ºC.…”

“…All potentials were adjusted to RHE and the potential of the reference electrode was determined by measuring the open circuit voltage of a Pt electrode in hydrogen saturated electrolyte. 29 Catalyst inks were prepared by adding 2.6 mg of catalyst to 0.5 ml of methanol and 38 μL of Nafion and sonicated for 20 minutes. The required volume for the 200 μg cm -2 was determined by depositing aliquots of the inks onto Al foil and weighing with a Mettler Toledo XP2U balance.…”