N-Doped Mo2C Nanobelts/Graphene Nanosheets Bonded with Hydroxy Nanocellulose as Flexible and Editable Electrode for Hydrogen Evolution Reaction

Abstract

SummaryThe large-scale application of economically efficient electrocatalysts for hydrogen evolution reaction (HER) is limited in view of the high cost of polymer binders (Nafion) for immobilizing of powder catalysts. In this work, nitrogen-doped molybdenum carbide nanobelts (N-Mo2C NBs) with porous structure are synthesized through a direct pyrolysis process using the pre-prepared molybdenum oxide nanobelts (MoO3 NBs). Nanocellulose instead of Nafion-bonded N-Mo2C NBs (N-Mo2C@NCs) exhibits superior performance toward HER, because of excellent dispersibility and multiple exposed catalytically active sites. Furthermore, the conductive film composed of N-Mo2C NBs, graphene nanosheets, and nanocellulose (N-Mo2C/G@NCs) is fabricated by simple vacuum filtration, as flexible and editable electrode, which possesses excellent performance for scale HER applications. This work not only proposes the potential of nanocellulose to replace Nafion for binding powder catalysts, but also offers a facile strategy to prepare flexible and conductive films for a wide variety of nanomaterials.

Charge Redistribution Caused by S,P Synergistically Active Ru Endows an Ultrahigh Hydrogen Evolution Activity of S‐Doped RuP Embedded in N,P,S‐Doped Carbon

“…The Tafel slope value of S-RuP@NPSC-900 (90.23 mV dec −1 ) was smaller than those of NPSC (364.36 mV dec −1 ), RuS 2 @NPSC-800 (352.67 mV dec −1 ), and S-RuP@NPSC-1000 (106.19 mV dec −1 ), and was larger than that of 20 wt% Pt/C (60.30 mV dec −1 ), confirming the desorption of H* (either the ion and atom reaction) was the ratedetermining step in HER reaction process (Heyrovsky-Volmer reaction). [9,32,45,46] It was worth emphasizing that RuS 2 @NPSC-800, S-RuP@NPSC-900, and S-RuP@NPSC-1000 possessed the ultralow loading amounts of Ru measured by ICP, which were 0.73, 0.8, and 0.85 wt%, respectively. Area and mass specific activity of RuS 2 @NPSC-800, S-RuP@NPSC-900, S-RuP@NPSC-1000, and 20 wt% Pt/C with the overpotential of 250 mV were calculated by the content of precious metals of Ru and Pt.…”

Applications of Nanocellulose/Nanocarbon Composites: Focus on Biotechnology and Medicine

“…Another important industrial application of nanocellulose/graphene composites is in energy storage, generation and conversion. Devices for these purposes include supercapacitors [64,80,130], hydrogen storage devices [131], electrodes for hydrogen evolution reaction [132], lithium ion batteries [133], actuators [81], solar steam generators [82] and electric heating membranes [83]. These devices can be based on pure nanocellulose/nanocarbon composites without additives [80][81][82][83].…”

“…However, they often contain additives such as manganese oxide (MnO), which contributes to faradaic pseudocapacitance in supercapacitors [130] or polypyrrole, which acts as an insulator, but its oxidized derivatives are good electrical conductors [134]. Other additives are palladium or platinum nanoparticles for enhanced hydrogen storage [131], nitrogen-doped molybdenum carbide nanobelts in electrocatalysts for hydrogen evolution reaction [132], and silicon oxide nanoparticles in lithium ion batteries [133].…”

Cathodic activation of synthesized highly defective monoclinic hydroxyl‐functionalizedZrO2nanoparticles for efficient electrochemical production of hydrogen in alkaline media

“…[3][4][5] Experimental findings revealed that the kinetics (expressed in exchange current density, j o ) of the HER in alkaline media is lower than that in acidic ones by 2 to 3 orders of magnitude. [6][7][8][9] Even on Pt, the most promising and highly efficient electrocatalyst for the HER, owing to its high reactivity for the adsorption and recombination of reactive H ads , 10 the HER exhibited slower kinetics in alkaline solutions, as compared to acidic ones. 11 The reduced efficacy of the water dissociation step on the Pt surface, Equation 6which constitutes an additional energy barrier to the kinetics of the overall reaction rate, is the main reason behind the sluggish kinetics of the alkaline HER on Pt surface.…”

“…Numerous publications reported that the HER on a wide range of electrocatalysts is pH‐dependent, generally decreases with increasing pH 3‐5 . Experimental findings revealed that the kinetics (expressed in exchange current density, j o ) of the HER in alkaline media is lower than that in acidic ones by 2 to 3 orders of magnitude 6‐9 . Even on Pt, the most promising and highly efficient electrocatalyst for the HER, owing to its high reactivity for the adsorption and recombination of reactive H ads , 10 the HER exhibited slower kinetics in alkaline solutions, as compared to acidic ones 11 .…”