Interfacial water engineering boosts neutral water reduction

Abstract

Hydrogen evolution reaction (HER) in neutral media is of great practical importance for sustainable hydrogen production, but generally suffers from low activities, the cause of which has been a puzzle yet to be solved. Herein, by investigating the synergy between Ru single atoms (RuNC) and RuSex cluster compounds (RuSex) for HER using ab initio molecular dynamics, operando X-ray absorption spectroscopy, and operando surface-enhanced infrared absorption spectroscopy, we establish that the interfacial water governs neutral HER. The rigid interfacial water layer in neutral media would inhibit the transport of H2O*/OH* at the electrode/electrolyte interface of RuNC, but the RuSex can promote H2O*/OH* transport to increase the number of available H2O* on RuNC by disordering the interfacial water network. With the synergy of RuSex and RuNC, the resulting neutral HER performance in terms of mass-specific activity is 6.7 times higher than that of 20 wt.% Pt/C at overpotential of 100 mV.

Acoustically‐Induced Water Frustration for Enhanced Hydrogen Evolution Reaction in Neutral Electrolytes

“…[36,61] Consequently, it has been suggested that disruption of the tetrahedral hydrogen bond network can, in principle, reduce the overpotential to effect enhancements in the HER rate by facilitating easier and more effective mass transport of the water molecules through the Debye layer. [35,37,38,[40][41][42]61,62] For example, it has been reported that an increase in the proportion of "frustrated" water of as little as 11%, which is similar to the 13.4% increase under the SRBW excitation observed here, was sufficient to result in an order-of-magnitude enhancement in current density [36,37] (cf. 14-fold enhancement obtained in the present work).…”

Stabilizing Copper by a Reconstruction-Resistant Atomic Cu–O–Si Interface for Electrochemical CO2 Reduction

“…Compared with CuGeO 3 or CuO, silica can effectively improve the stability of Cu–O bond, thereby improving the electrochemical stability of Cu–O–Si interface sites during CO 2 R process, which is consistent with the in situ XAS experiment results. Subsequently, we constructed the structural model of CuSiO x according to the element ratios (Table S4) and performed AIMD simulations in the canonical ensemble ( NVT ) to optimize the structural model . As shown in Figure c, the system was followed by 20 ps of simulation with a time step of 2 fs to give the final stable CuSiO x structure, in which each Cu atom was connected with 4 or 3 O atoms and formed an amorphous structure (Figures b and S26), which is consistent with the HRTEM and XAS results.…”

Defect engineering of two-dimensional materials for advanced energy conversion and storage

“…, the Tafel step: H* + H* → H 2 , or the Heyrovsky step: H* + H + + e − → H 2 ), and the desorption of H 2 . 252–255 To evaluate reactions from the thermodynamic point of view, the free energy of hydrogen adsorption (Δ G H* ) can now be quantified by theoretical calculations. According to the principle of Sabatier, the closer the Δ G H* value is to zero the higher the HER activity.…”

“…242,250,251 Generally, the HER process on the electrocatalyst surface is divided into three steps: the adsorption of hydrogen ions at active sites (*) (i.e., the Volmer step: H + + e À + * -H*), the formation of hydrogen molecules (i.e., the Tafel step: H* + H* -H 2 , or the Heyrovsky step: H* + H + + e À -H 2 ), and the desorption of H 2 . [252][253][254][255] To evaluate reactions from the thermodynamic point of view, the free energy of hydrogen adsorption (DG H* ) can now be quantified by theoretical calculations. According to the principle of Sabatier, the closer the DG H* value is to zero the higher the HER activity.…”