abstract
Considerable improvements in the electrocatalytic activity of 2D metal phosphorous trichalcogenides (M2P2X6) have been achieved for water electrolysis, mostly with M-2(II)[P2X6](4-) as catalysts for hydrogen evolution reaction (HER). Herein, (MMP2S6)-M-I-P-III (M-I = Cu, Ag; M-III = Sc, V, Cr, In) are synthesized and tested for the first time as electrocatalysts in alkaline media, towards oxygen reduction reaction (ORR) and HER. AgScP2S6 follows a 4 e(-) pathway for the ORR at 0.74 V versus reversible hydrogen electrode; CuScP2S6 is active for HER, exhibiting an overpotential of 407 mV and a Tafel slope of 90 mV dec(-1). Density functional theory models reveal that bulk AgScP2S6 and CuScP2S6 are both semiconductors with computed bandgaps of 2.42 and 2.23 eV, respectively and overall similar electronic properties. Besides composition, the largest difference in both materials is in their molecular structure, as Ag atoms sit at the midpoint of each layer alongside Sc atoms, while Cu atoms are raised to a similar height to S atoms, in the external segment of the 2D layers. This structural difference probably plays a fundamental role in the different catalytic performances of these materials. These findings show that M-I(Cu, Ag) together with Sc(M-III) leads to promising achievements in (MMP2S6)-M-I-P-III materials as electrocatalysts.
keywords
HYDROGEN EVOLUTION; LAMELLAR COMPOUND; CRYSTAL-STRUCTURE; OXYGEN REDUCTION; ELECTROCATALYSTS; THIOPHOSPHATE; TRENDS
subject category
Chemistry; Science & Technology - Other Topics; Materials Science
authors
Oliveira, FM; Pastika, J; Plutnarová, I; Mazánek, V; Strutynski, K; Melle-Franco, M; Sofer, Z; Gusmao, R
our authors
Karol Strutyński
Assistant Researcher
Manuel Melle-Franco
Principal ResearcherProjects
Projeto de Investigação Exploratória: Manuel Melle (IF Manuel Melle)
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
The authors acknowledge support from the Czech Science Foundation through the GACR Project No. 20-21523Y. In addition, support through the project IF/00894/2015 and within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC) is gratefully acknowledged.