Interfacial Water Activation by Single-Atom Co–N₃ Sites Coupled with Encapsulated Co Nanocrystals for Accelerating Electrocatalytic Hydrogen Evolution

Abstract

Using high-efficiency and low-cost catalyst to replace noble metal platinum for electrocatalytic hydrogen evolution reaction (HER) provides a broad prospect for the development of renewable energy technology, which is an important task yet to be solved. Herein, we proposed an efficient doping–adsorption–pyrolysis strategy for constructing a robust coupling catalyst composed of single-atom Co–N3 sites anchored on an N-doped carbon (N–C) layer and encapsulated Co nanocrystals (NCs) to activate the interfacial water for accelerating HER. Beneficial to the strong synergistic effect of Co–N3 sites and Co NCs, the optimized CoNC‑SA/N*–C catalyst showed excellent HER activity and stability in both acidic and alkaline electrolytes. In situ attenuated total reflectance–surface-enhanced infrared absorption spectroscopy revealed that the rigid interfacial water layer of Co–N3 sites inhibited the transport of H2O*/OH*, while Co NCs promoted the transport of H2O*/OH* and increased the amount of available H2O* on Co–N3 sites by disordering the rigid interfacial water network. Theoretical calculation showed that the coupling interface structure destroyed the rigid interfacial network, and Co NCs modified the electronic structure of Co–N3 sites, which is beneficial to H2O dissociation and H adsorption, thus accelerating the HER process. This work opens up new avenues for the construction of coupling catalysts from the atomic scale to activate the interfacial water for boosting HER electrocatalysis.

Interfacial water engineering boosts neutral water reduction

“…Notably, the liquid-like water and the free water are the unique structures of the interfacial water in alkaline media, while and shifting to more negative potentials results in more free water. In alkaline media, the non-specifically adsorbed OH – anions may promote the H 2 O*/OH* to go through the interfacial water layer, generating more free water molecules to approach the active sites as proton donors to participate in the surface catalytic processes, which is consistent with the Volmer step (H 2 O + e − → H* + OH − ) 46 , 47 .…”

Designing strategies and enhancing mechanism for multicomponent high-entropy catalysts

“…As is well-known, DFT is a powerful weapon to verify the experimental results by calculating the energy of formation of oxygen vacancies, Gibbs free energy difference (ΔG) diagrams, density of states (DOS), charge distribution analysis and their behavior under strain. [109][110][111] Therefore, the employ of reasonable theoretical pathway reveals a mixture of Ru, Ir and possibly a small amount of Rh as the optimum.…”

“…As is well known, DFT is a powerful weapon to verify the experimental results by calculating the energy of formation of oxygen vacancies, Gibbs free energy difference (DG) diagrams, density of states (DOS), charge distribution analysis and their behavior under strain. [109][110][111] Therefore, the use of reasonable theoretical calculation/prediction could help researchers to develop efficient catalysts more easily from a large composition space. For high-entropy catalysts, the different local atomic environments lead to a distribution of binding energy for the catalytic intermediates, among which specic sites may reach the maximum activity on the basis of the Sabatier principle.…”

Inheritable Organic‐Inorganic Hybrid Interfaces with π–d Electron Coupling for Robust Electrocatalytic Hydrogen Evolution at High‐Current‐Densities

“…[ 1–3 ] Therefore, non‐precious metal electrocatalysts design is the key to reducing the cost of water splitting. [ 4–6 ] Among many design strategies, heterointerface engineering has been widely used to regulate the activity of non‐precious metal catalysts. [ 7–10 ] Reasonable interfacial contacts can improve the activity of interfacial sites via charge interaction while preserving the typical characteristics of individual materials.…”