Recent Advances in Multimetal and Doped Transition-Metal Phosphides for the Hydrogen Evolution Reaction at Different pH values

Abstract

Hydrogen is a fuel with a potentially zero-carbon footprint viewed as a viable alternative to fossil fuels. It can be produced in a large scale via electrochemical water splitting using electricity derived from renewable sources, but this would require highly active, inexpensive, and stable hydrogen evolution reaction (HER) catalysts to replace the Pt benchmark. Transition-metal phosphides (TMPs) are potential Pt replacements owing to their generally high activity as well as versatility as HER catalysts for different pH media. This review summarizes the recent progress in the development of TMP HER electrocatalysts, focusing on the strategies that have been recently explored to tune the activity in acidic, neutral, and basic media. These strategies are the doping of TMPs with metal and nonmetal elements, fabrication of multimetallic phosphide phases, and construction of multicomponent heterostructures comprising TMPs and another component such as a different TMP or a metal oxide/hydroxide. The synthetic methods utilized to design the catalysts are also presented. Finally, the challenges still remaining and future research directions are discussed.

Covalent Functionalization of Nickel Phosphide Nanocrystals with Aryl-Diazonium Salts

“…[16][17][18][19] This same line of theory driven inquiry led to the investigation of transition metal phosphides as a new class of materials with excellent catalytic activity for HER and high stability in acidic media. Research efforts over the past decade have explored many aspects of these materials including synthetic methodology and mechanisms 20,21,30,[22][23][24][25][26][27][28][29] , the effects of varying atomic composition [31][32][33][34] , nano-structuring [35][36][37] , and computational modeling of their catalytically active surface sites. 31,[38][39][40][41][42][43][44] Despite great progress in developing this class of materials, earth abundant alternatives still present orders of magnitude lower activity than their precious metal counterparts.…”

Bridging electrocatalyst and cocatalyst studies for solar hydrogen production via water splitting

“…27,28 Metal (Ni, Co, Fe, W, Mo, …) phosphides, nitrides, and carbides are also subjects of extensive studies owing to their advantageous electronic structures. 27,29–38 Tuning the metal composition has proven to be pivotal in realizing exceptional HER performance. 29 Such rationally designed EC compounds have realized comparable HER activities over a wide range of pH for practical applications.…”

Electronic Structure and d-Band Center Control Engineering over Ni-Doped CoP3 Nanowall Arrays for Boosting Hydrogen Production

“…Among such TMPs, Co phosphides (Co 2 P, CoP, CoP 2 , and CoP 3 ) have attracted much research interest owing to their fine electrocatalytic performance and stability [ 14 , 15 , 16 , 17 ]. Moreover, heteroatom doping can tune the electronic structures and energy-level modulation so as to tune the HER electrocatalytic capability and to reduce the hydrogen adsorption free energy in catalysts [ 18 , 19 , 20 ]. Thus far, Fe-, Mn-, Cu-, and N-doped Co 2 P and CoP have been studied extensively [ 21 , 22 , 23 , 24 ], with the results indicating that the doped CoP and Co 2 P exhibit enhanced electrochemical performance compared with undoped electrocatalysts.…”