Carbon Nanotubes Decorated with CoP Nanocrystals: A Highly Active Non‐Noble‐Metal Nanohybrid Electrocatalyst for Hydrogen Evolution

Abstract

The development of effective and inexpensive hydrogen evolution reaction (HER) electrocatalysts for future renewable energy systems is highly desired. The strongly acidic conditions in proton exchange membranes create a need for acid-stable HER catalysts. A nanohybrid that consists of carbon nanotubes decorated with CoP nanocrystals (CoP/CNT) was prepared by the low-temperature phosphidation of a Co3O4/CNT precursor. As a novel non-noble-metal HER catalyst operating in acidic electrolytes, the nanohybrid exhibits an onset overpotential of as low as 40 mV, a Tafel slope of 54 mV dec(-1), an exchange current density of 0.13 mA cm(-2), and a Faradaic efficiency of nearly 100 %. This catalyst maintains its catalytic activity for at least 18 hours and only requires overpotentials of 70 and 122 mV to attain current densities of 2 and 10 mA cm(-2), respectively.

Highly branched cobalt phosphide nanostructures for hydrogen-evolution electrocatalysis

“…Indeed, comparable HER activity has been observed by several groups for CoP materials that span a range of morphologies, synthetic protocols, accessible surface areas, and support materials. [4][5][6][7][8][9][10][11] A key nding of this work is that the activities are largely the same, regardless of morphology or preparation method, underscoring the high intrinsic activity of CoP. The intrinsic HER activity of CoP makes it a highly viable candidate for practical applications, regardless , along with Ti foil and Pt mesh electrodes for comparison.…”

Operando Spectroscopic Analysis of CoP Films Electrocatalyzing the Hydrogen-Evolution Reaction

“…[15][16][17][18][19] Electrodeposited CoP films effect the HER at a current density of -10 mA cm -2 with - < 100 mV in acidic solution (pH < 1). 20 Characterization of this material, as well as related metal phosphides, has relied principally upon ex-situ techniques that typically involve analysis in vacuum or laboratory ambients.…”

3D Nanoporous Metal Phosphides toward High‐Efficiency Electrochemical Hydrogen Production

“…[ 16,17 ] Currently, the nanostructured metal phosphides are mainly synthesized by solvothermal methods [ 16,18 ] and phosphidation of nanostructured transition metal oxides/hydroxides, [ 17,20,21 ] which often suffer from inevitable environmental pollutions from phosphorization process, less electrochemical stability from the inadequate contact with conductive supports and binders, and low energy effi ciency from high internal resistance. [16][17][18]20 ] In this study, …”