Tuning and mechanistic insights of metal chalcogenide molecular catalysts for the hydrogen-evolution reaction

Abstract

The production of hydrogen through water splitting using earth-abundant metal catalysts is a promising pathway for converting solar energy into chemical fuels. However, existing approaches for fine stoichiometric control, structural and catalytic modification of materials by appropriate choice of earth abundant elements are either limited or challenging. Here we explore the tuning of redox active immobilised molecular metal-chalcoxide electrocatalysts by controlling the chalcogen or metal stoichiometry and explore critical aspects of the hydrogen evolution reaction (HER). Linear sweep voltammetry (LSV) shows that stoichiometric and structural control leads to the evolution of hydrogen at low overpotential with no catalyst degradation over 1000 cycles. Density functional calculations reveal the effect of the electronic and structural features and confer plausibility to the existence of a unimolecular mechanism in the HER process based on the tested hypotheses. We anticipate these findings to be a starting point for further exploration of molecular catalytic systems.

The rapid electrochemical activation of MoTe2 for the hydrogen evolution reaction

“…The Tafel slope of nanocrystalline 1T′-MoTe 2 undergoes an increase from 68 ± 4 mV decade −1 when inactivated to 116 ± 17 mV decade −1 after activation, thus indicating that the activation process results in the discharge (Volmer) step now being rate-limiting 13–15 . Upon cycling, there are also substantial changes in the exchange current density (from extrapolation of the Tafel slopes) and turnover frequency, with these parameters peaking at 0.503 mA cm −2 and 0.12 s −1 at 0 mV respectively after 100 cycles (Supplementary Table 2).…”

Autocatalysis: Kinetics, Mechanisms and Design

“…Miras et al. constructed different auto‐ and cross‐catalytic cycles that form molybdenum nanoclusters with different compositions [72] . Autocatalytic kinetics seems to be a general trend in reactions involving the reduction of metals to their metallic form.…”

“…Miras et al constructed different auto-and cross-catalytic cycles that form molybdenum nanoclusters with different compositions. [72] Autocatalytic kinetics seems to be a general trend in reactions involving the reduction of metals to their metallic form. Reduction of silver halides in photographic processes and reduction of nickel salts during electroless plating are representative examples.…”

Devisable POM/Ni Foam Composite: Precisely Control Synthesis toward Enhanced Hydrogen Evolution Reaction at High pH

“…Compared with the electrolysis process in acidic media, HER in alkaline electrolysis is more favourable for electrochemical water splitting due to the robustness of electrode materials, long lifetime of catalysts, cheap electrolyser construction and less equipment corrosion . However, HER reaction rate for most catalysts in alkaline solution is 2–3 orders of magnitude lower than that in acidic solution, and HER application is largely limited by sluggish kinetics in alkaline solution. Therefore, significant studies are focusing on the development of electrocatalysts to overcome the high energy barriers and slow kinetics of HER reaction in alkaline solution.…”