Hydrogen Evolution Reaction Activity of Graphene-MoS2 van der Waals Heterostructures

Biroju, Ravi K and Das, Deya and Sharma, Rahul and Pal, Shubhadeep and Mawlong, Larionette P L and Bhorkar, Kapil and Giri, P K and Singh, Abhishek K and Narayanan, Tharangattu N (2017) Hydrogen Evolution Reaction Activity of Graphene-MoS2 van der Waals Heterostructures. In: ACS ENERGY LETTERS, 2 (6). pp. 1355-1361.

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Abstract

Determining a suitable noble-metal-free catalyst for hydrogen evolution reaction (HER) by photo-electrocatalytic (PEC) water splitting is an enduring challenge. Here, the molecular origin of number of layers and stacking sequence-depen'dent PEC HER performance of MoS2/graphene (MoS2/GR) van der Waals (vdW) vertical heterostructures is studied. Density functional theory (DFT) based calculations show that the presence of MoS2 induces p-type doping in GR, which facilitates hydrogen adsorption in the GR side compared to the MoS2 side with Delta GH closer to 0 eV in the MoS2/GR bilayer vertical stacks. The activity maximizes in graphene with monolayer MoS2 and reduces further for bilayer and multilayers of MoS2. The PEC HER performance is studied in various electrodes, namely, single-layer graphene, single- and few-layered MoS2, and their two different types of vertical heterojunctions having different stacking sequences. The graphene on top of MoS2 sequence showed the highest photoresponse with large reaction current density and lowest charge-transfer resistance toward HER, in aggrement with the DFT calculations. These findings establish the role of stacking sequence in the electrochemistry of atomic layers, leading to the design of new electrocatalysts by combinatorial stacking of a minimal number of layers.

Item Type:	Journal Article
Publication:	ACS ENERGY LETTERS
Additional Information:	Copyright for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	08 Jul 2017 07:05
Last Modified:	08 Jul 2017 07:05
URI:	http://eprints.iisc.ac.in/id/eprint/57325

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