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Simultaneously optimizing elementary steps, such as water dissociation, hydroxyl transferring, and hydrogen combination, is crucial yet challenging for achieving efficient hydrogen evolution reaction (HER) in alkaline media. Herein, Ru single atom‐doped WO2 nanoparticles with atomically dispersed Ru–W pair sites (Ru–W/WO2‐800) are developed using a crystalline lattice‐confined strategy, aiming to gain efficient alkaline HER. It is found that Ru–W/WO2‐800 exhibits remarkable HER activity, characterized by a low overpotential (11 mV at 10 mA cm−2), notable mass activity (5863 mA mg−1 Ru at 50 mV), and robust stability (500 h at 250 mA cm−2). The highly efficient activity of Ru–W/WO2‐800 is attributed to the synergistic effect of Ru–W sites through ensemble catalysis. Specifically, the W sites expedite rapid hydroxyl transferring and water dissociation, while the Ru sites accelerate the hydrogen combination process, synergistically facilitating the HER activity. This study opens a promising pathway for tailoring the coordination environment of atomic‐scale catalysts to achieve efficient electro‐catalysis. [ABSTRACT FROM AUTHOR]

Accelerating slow water dissociation kinetics is key to boosting the hydrogen evolution reaction (HER) in alkaline media. We report the synthesis of atomically dispersed MoOx species anchored on Rh metallene using a one‐pot solvothermal method. The resulting structures expose the oxide‐metal interfaces to the maximum extent. This leads to a MoOx‐Rh catalyst with ultrahigh alkaline HER activity. We obtained a mass activity of 2.32 A mgRh−1 at an overpotential of 50 mV, which is 11.8 times higher than that of commercial Pt/C and surpasses the previously reported Rh‐based electrocatalysts. First‐principles calculations demonstrate that the interface between MoOx and Rh is the active center for alkaline HER. The MoOx sites preferentially adsorb and dissociate water molecules, and adjacent Rh sites adsorb the generated atomic hydrogen for efficient H2 evolution. Our findings illustrate the potential of atomic interface engineering strategies in electrocatalysis. [ABSTRACT FROM AUTHOR]

For electrocatalysts for the hydrogen evolution reaction (HER), encapsulating transition metal phosphides (TMPs) into nitrogen‐doped carbon materials has been known as an effective strategy to elevate the activity and stability. Yet still, it remains unclear how the TMPs work synergistically with the N‐doped support, and which N configuration (pyridinic N, pyrrolic N, or graphitic N) contributes predominantly to the synergy. Here we present a HER electrocatalyst (denoted as MoP@NCHSs) comprising MoP nanoparticles encapsulated in N‐doped carbon hollow spheres, which displays excellent activity and stability for HER in alkaline media. Results of experimental investigations and theoretical calculations indicate that the synergy between MoP and the pyridinic N can most effectively promote the HER in alkaline media. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) are currently one of the most active forefronts in heterogeneous catalysis. The vast majority of SACs are coordinated by highly electronegative heteroatoms like N and O, which often results in electron-deficient SACs and undesirable catalytic performance. Tuning the coordination environment of SACs by low-electronegativity species is essential, yet to date remains largely unexplored. Here, few-layer violet phosphorene (VP) was used as a giant phosphorus ligand to confine Ni single-atoms via a photoreduction approach. Combined experimental analysis and density-functional theory calculations confirmed that VP nanosheets covalently stabilized monovalent Ni (I) single-atoms in a Ni-P 4 atomic configuration. The active and durable Ni-P 4 moieties were shown to reduce the work function and band gap, optimize proton adsorption, and facilitate photoexcited charge separation, synergistically leading to a maximal hydrogen evolution rate of 377.8 μmol h−1g−1 which is an 11-fold increase than that of VP nanosheets. This work paves an avenue for the exploration of VP's enormous potential in solar-driven artificial photosynthesis as well as provides guidance to the rational design of P-coordinated SACs for diverse applications beyond water splitting. [Display omitted] • Immobilize single Ni atoms on few-layer VP via photoreduction deposition. • Identify atomically dispersed Ni-P4 moieties linked by Ni-P covalent-like bonds. • Achieve a hydrogen evolution rate which is 11-fold greater than that of VP nanosheets. • Reveal a synergy of local electronic structure, proton adsorption and charge separation on enhancing photoactivity. • Pave a path to the rational design of viable P-coordinated SACs. [ABSTRACT FROM AUTHOR]

• Mo 2 C/CFP-Act is prepared via continuous cathode polarization technique. • Mo 2 C/CFP-Act is an excellent electrocatalyst for the hydrogen evolution reaction. • Mechanism study unveils the Pt single atom intrinsic role in Mo 2 C/CFP catalysts. Dispersing catalytically active metals as single atoms on supports offer an efficient pathway to minimize amount of precious metals. Although platinum (Pt) is highly active for HER, it is highly desirable to find ways to improve the HER performance and also keeping them stable during catalytic reactions while minimizing the Pt loading. Herein, we report a cathode polarization technique to disperse isolated single Pt atoms on β-Mo 2 C as a catalyst for HER. The isolated Pt atoms partially occupy Mo sites in Mo 2 C lattice by forming Pt-Mo shells, which maximize the utilization ratio of platinum noble metals. The single atoms catalyst Mo 2 C/CFP-Act even exhibited 1.9 and 1.1 times higher current density (@ potential of 0.4 V vs. RHE) than that of Pt NPs catalysts (Mo 2 C/CFP-Pt) after mass normalization in both acidic and alkali solution. Furthermore, DFT calculations demonstrate that Mo 2 C/CFP-Act exhibits favorable ΔG H* for the adsorption and desorption of hydrogen. The high HER activity of the Mo 2 C/CFP-Act catalyst is related to the Mo-Pt center located in Mo 2 C matrix, where the electronic structure of the Mo-Pt centers more efficient in donating electron to the σ* antiorbital of the H 3 O+ molecule. This study sheds new light on the HER catalysis mechanism of isolated metal atoms based on fundamental understanding in molecular governing factors. [ABSTRACT FROM AUTHOR]