Paper-Based Flexible and Photosensitive Electrodes for Electrochemical Hydrogen Evolution

Abstract

We report the fabrication of a flexible and photosensitive electrode for electrocatalysis using efficient, robust, and photosensitive two-dimensional molybdenum disulfide (2D-MoS 2 ) nanosheets and flexible, lightweight, large area, and conducting Agmetal coated cellulose paper. The MoS 2 /Ag electrode shows a electrocatalytic activity with an overpotential of −250 mV versus the reversible hydrogen electrode (vs RHE) at a cathodic current density of −10 mA/cm 2 because of the low charge transfer resistance. The electrode exhibits stability upto 17 h at a high cathodic current density of ≈ −44 mA/ cm 2 at −400 mV versus RHE. The MoS 2 /Ag cathode shows enhanced hydrogen evolution reaction activity under visible light and facilitates a faster catalytic reaction with an overpotential as low as −190 mV versus RHE. The photosensitive cathode demonstrates self-powered photodetection ability in acidic medium because of the optimized interaction of the OH/surface active sites and the presence of a built-in electric field at the MoS 2 /Ag interface. Overall, the present finding on flexible electrodes for electrocatalysis advocates the upsurge of applications of photosensitive electrodes in clean energy generation.

Edge Rich Ultrathin Layered MoS2 Nanostructures for Superior Visible Light Photocatalytic Activity

“…SI Figure S4c,d present the elementary EDS (energy dispersion spectroscopy) mapping of Mo and S for MoS 2 nanoflowers. It is noticeable that the distribution of Mo and S atoms in the layered MoS 2 nanoflowers was homogeneous. − …”

Enhanced electrocatalysis of WSe 2 nanosheets by partial oxidation for hydrogen generation

“…(A) Overpotential required for hydrogen evolution reaction for photosensitive electrodes for 2D‐TMDCs, 7–9,50 (B) Schematic diagram of charge transport in WSe 2 /WO 3−x under light illumination…”

“…Chen et al demonstrate the high-performance electrocatalytic hydrogen evolution reaction on rhodium-iridium nanosheets on Nickel foam over a wide pH range with extremely low overpotential due to high conductivity and synergistic effect of the bimetals, as well as the enlarged electrochemical surface area (ECSA). 1 For example, graphene, 2 transition metal dichalcogenides (TMDCs) [3][4][5][6][7][8][9] and oxides, 8 metal hydroxides, 10,11 polymers like polyaniline, 7 etc. The majority of these materials show poor electrocatalytic behaviour owing to the limited concentration of catalytically active sites and high overpotential for water splitting.…”

“…5,20,21 So far, most of the research was focused on the improvement of intrinsic electrocatalytic properties by enhancing the ECSA and has ignored the development of the photosensitive nature. Recently, a few photosensitive hybrid materials like metals decorated 2D-TMDCs including Ag/WS 2 , 5 Ni/WS 2 , 22 Au/MoS 2 , 20 MoS 2 /Ag, 9 etc have been developed for promising electrocatalytic reaction under visible light illumination owing to LSPR resonances of metals and excitonic resonances of 2D-TMDCs. Even solar heating during electrocatalysis causes the fast diffusion of electrolyte ions in electrode materials which enhances the rate of electron transport and reduces the overpotential for water electrolysis.…”

Optical Switching Device Based on a Crystalline SnSe2 Photodetector in Diverse Conditions

“…Layered materials are tremendously considered compounds that exhibit tunable optoelectronics properties and dependency on the number of layers. − The weak interlayer contact leads to the withdrawal of monolayer or a few layers of atoms conceivable, thus leading to the escalation of exploring the reduced dimensional form of material along with their superior optoelectronic and water splitting applications. − Among layered materials, metal chalcogenides are widely investigated materials because of their noteworthy photosensing capabilities, which increased their utility value for the fabrication of advanced solid-state devices based on photonics. − Particularly in metal dichalcogenides, SnSe 2 is the utmost explored material due to its superior thermoelectric nature, photoconductivity, gas sensing ability, and substantial aptitude to form a heterojunction with other two-dimensional (2D) materials that resulted in the advancement of solid-state device application such as photodetectors, Schottky as well as field-effect transistor (FET) devices, and solar cells. − Owing to the hexagonal lattice configuration of CdI 2 type with the P 3̅ m 1 space group and preferred crystallization in 2-H as well as 1-T polytype, SnSe 2 discloses the laminar structure in which Sn is the metal atom and Se is the chalcogen atom exhibiting the n-type semiconductive nature. Here, the Sn atom is strongly bonded with two Se atoms in a sandwiched form within the same plane and forming a Se–Sn–Se sheet that also weakly stacked upon another similar sheet by van der Waals interaction. , …”