One-Step Hydrothermal Synthesis of Phase-Engineered MoS2/MoO3 Electrocatalysts for Hydrogen Evolution Reaction

By Shanmughasundaram Duraisamy, A. Ganguly, P. Sharma, J. Benson, James Davis, P. Papakonstantinou. ACS Applied Nano Materials, 2021

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: The development of suitable approaches for the synthesis of ultrathin transition-metal dichalcogenide (TMD) catalysts is required to engineer phases, intercoupling between di ﬀ erent phases, in-plane defects, and edges and hence maximize their catalytic performance for hydrogen production. In this work, we report a simple one-step hydrothermal approach for the synthesis of a three-dimensional (3D) network of self-assembled metallic MoS 2 /MoO 3 nanosheets, using α -MoO 3 and thiourea (TU) as the Mo and S precursors, respectively. A systematic structural/property relationship study, while varying the precursors ’ molar concentration ratios (TU/MoO 3 ) and reaction temperatures ( T R ), revealed a kinetically controlled regime, in hydrothermal synthesis, that enabled the formation of ultrathin branched MoS 2 /MoO 3 nanosheets with the highest metallic content of ∼ 47 % in a reproducible manner. Importantly, the work established that in addition to the rich metallic MoS 2 phase (1T), the electronically coupled interfaces between MoO 3 and MoS 2 nanodomains, profusion of active sites, and tuned electrical conductivity signi ﬁ cantly contributed to hydrogen evolution reaction (HER)-catalytic activity, a ﬀ ording a low overpotential of 210 mV (with respect to the reversible hydrogen electrode) at a current density of 10 mA/cm 2 , a small Tafel slope of ∼ 50 mV/dec, and high stability. Overall, this work demonstrated a controllable one-step hydrothermal method for the rational design and synthesis of a 3D network of MoS 2 /MoO 3 nanosheets with high 1T-MoS 2 metallic yield, simultaneous incorporation of MoO 3 /MoS 2 heterointerfaces, sulfur vacancies, and tuned electrical conductivity, which are highly bene ﬁ cial for clean energy conversion applications that can potentially be expanded to other two-dimensional TMD materials

Subfields: Materials Chemistry, Renewable Energy, Sustainability and the Environment

View Paper: https://www.semanticscholar.org/paper/223e26bfa53e6c74d44df4b549b5d2bb4c9325b0