Phase Control of Cobalt Selenide: Unraveling the Relationship Between Phase Property and Hydrogen Evolution Catalysis

Abstract

electric or solar energy as a driving force is a promising measure to realize the generation of green energy source. [1,2] However, electro-and photocatalytic hydrogen evolution reaction (HER) both confront a big challenge regarding the conversion efficiency and economical cost. [3][4][5][6] There are two general concerns for the two mentioned HER pathway, that is the low charge transport efficiency and surface reactivity. [7][8][9] Therefore, material design to overcome the general shortcomings for HER is urgent to boost the performance.Structural engineering of nanomaterials has been proven as a powerful pathway to tune their physico-chemical and electronic properties, and thus resulting in improved catalytic performance. [10][11][12] Transitional metal dichalcogenides (TMDs) represented by MoS 2 are advancing catalysts for HER, owing to the hydrogen adsorption ability and earth-abundant characteristics. [13][14][15] Recent reported structural engineering strategies for TMDs generally focus

Deciphering the Influence of Morphology and Crystal Structure on Alkaline Hydrogen Evolution Activity in Polymorphic Cobalt Diselenide

“…Based on all the above characterization and observed HER results, it is evident that both the catalysts based on CoSe 2 polymorphs (o-CoSe 2 and c-CoSe 2 ) despite their differing crystal structures and morphologies exhibit comparable HER performance. As per previous reports, CoSe 2 -based HER electrocatalysts with the same morphology but different crystal structures have resulted in markedly different HER activity that is attributed to their different electronic structure and hydrogen adsorption energy at the Co sites . In another instance, the HER performance of orthorhombic CoSe 2 is also reported to be morphology dependent because of the different electrochemically active surface areas they offered resulting in dissimilar reaction rates .…”

“…As per previous reports, CoSe 2 -based HER electrocatalysts with the same morphology but different crystal structures have resulted in markedly different HER activity that is attributed to their different electronic structure and hydrogen adsorption energy at the Co sites. 27 In another instance, the HER performance of orthorhombic CoSe 2 is also reported to be morphology dependent because of the different electrochemically active surface areas they offered resulting in dissimilar reaction rates. 31 Furthermore, Yang's group reported that CoSe 2 /HC as well as p-CoSe 2 @HC (here HC represents hollow mesoporous carbon nanospheres) with the same crystal structure (mixture of orthorhombic and cubic phases) and similar nanoparticle-like morphology can exhibit different HER performances due to presence of different number of active sites.…”

“…For instance, Zhou et al prepared o-CoSe 2 via a wet-chemical approach and then synthesized c-CoSe 2 by annealing metastable o-CoSe 2 . 27 Their findings reveal that o-CoSe 2 exhibits higher HER catalytic activity with an overpotential 30 Additionally, other studies have focused on unraveling the morphology-dependent HER activities of CoSe 2 while keeping the crystal structures same. For instance, Feng's group prepared two different morphologies (agaric-like and nanorod-like) of orthorhombic CoSe 2 to study the effect of morphology on the HER performance.…”

“…These studies aimed to elucidate the relationship between phase structures and catalytic performance, discerning whether the orthorhombic or cubic phase performs better in the HER. For instance, Zhou et al prepared o-CoSe 2 via a wet-chemical approach and then synthesized c-CoSe 2 by annealing metastable o-CoSe 2 . Their findings reveal that o-CoSe 2 exhibits higher HER catalytic activity with an overpotential (η 10 ) of 300 mV at a current density of 10 mA cm –2 compared to c-CoSe 2 (η 10 = 365 mV) in 0.5 M H 2 SO 4 solution because of the appropriate hydrogen adsorption capacity (Δ G H * = 0.27 eV at Co sites) of the former.…”

Construction of core–shell CoSe2/ZnIn2S4 heterostructures for efficient visible-light-driven photocatalytic hydrogen evolution

“…The inherent properties of CoSe 2 endowed it with high electronic conductivity and proton adsorption ability, while its low cost and stable chemical properties made it a potential substitute for noble metals. 31–34 As reported by Jia et al , a binary CoSe 2 /g-C 3 N 4 composite photocatalyst was rationally fabricated, 35 in which the presence of CoSe 2 significantly facilitated charge transfer and the separation of photoinduced charge, contributing to elevated photocatalytic hydrogen evolution activity and excellent stability. However, most of the preparation processes required high-temperature heat treatment, which contradicted the concept of energy conservation and possessed certain risks.…”