Development of highly active hydrogen evolution reaction (HER) catalysts composed of reduced graphene oxide and amorphous molybdenum sulfides derived from (NH4)2MoOmS4-m (m = 0, 1, and 2)

Peripherally and non-peripherally carboxylic acid substituted Cu(ii) phthalocyanine/reduced graphene oxide nanohybrids for hydrogen evolution reaction catalysts

“…7). In acidic media, the production of H 2 takes place in three steps: 102 H 3 O + + e − → H ads + H 2 O (Volmer reaction)H 3 O + + e − + H ads → H 2 + H 2 O (Heyrovsky reaction)H ads + H ads → H 2 (Tafel reaction)The production of H 2 in the acidic medium was proposed by the following reactions: Volmer, Heyrovsky, and Tafel. Tafel slopes for rGO/CuPc( 1 ), rGO/CuPc( 2 ) and rGO/CuPc( 3 ) are calculated to be 302, 231, and 173 mV dec −1 , respectively, indicating increasing HER performance from rGO/CuPc( 1 ) to rGO/CuPc( 3 ).…”

Electrochemical Potential-Dependent Stability and Activity of MoS3 during the Hydrogen Evolution Reaction

“…Our interpretation of the reactivity of Mo 3 S 7 induced by OH groups can be fruitfully compared with some experimental results by Tran et al revealing that top S 2 2– species are eliminated and replaced by reactive oxygenated atoms. Also, other experimental studies invoked that the partial oxidation of the MoS 3 phase could be at the origin of the HER activity. , …”

“…32 Along the same line, several experimental studies suggested that partially oxidized (a-MoOS 3 ) species could be even better for HER catalytic activity. 15,33,34 In the same spirit, Escalera-Loṕez et al have shown that, depending on pH conditions, the unsaturated S, top S 2 2− species, and to some extent, sulfur deficient, oxygen-containing Mo sites could be active sites for HER in a-MoS 3 . 12 Abidi et al examined the stability of MoS 2 -edges under electrochemical potential and evidenced possible HER mechanisms including edge reconstructions due to H 2 S-release and involving OH-based HER active sites.…”

“…However, a reverse conclusion had been reached by an earlier study, leaving the question unsettled . Along the same line, several experimental studies suggested that partially oxidized ( a -MoOS 3 ) species could be even better for HER catalytic activity. ,, In the same spirit, Escalera-López et al have shown that, depending on pH conditions, the unsaturated S, top S 2 2– species, and to some extent, sulfur deficient, oxygen-containing Mo sites could be active sites for HER in a -MoS 3 …”

Elucidating active sites and decomposition mechanisms for oxythiomolybdate clusters (Mo2O2Sx, x = 6;8) as catalyzers for hydrogen evolution reactions

“…One alternative for MoS x clusters is thiomolybdates (e.g., MoO(S 2 ) 2 ), which are used through homogeneous catalysis for HER, [24][25][26] and oxythiomolybdates also appeared as a good candidate for HER. [27,28] This study aims to investigate Mo 2 O 2 S x (x = 6,8) [26,29,30] and, particularly, the possible mechanism of degradation during HER, comparing Mo 2 O 2 S x with Mo 3 S 13 , and to evaluate the effects of different solvents, and the mechanism of hydrogen absorption.…”