Heteroatom‐Mediated Interactions between Ruthenium Single Atoms and an MXene Support for Efficient Hydrogen Evolution

Abstract

A titanium carbide (Ti3C2Tx) MXene is employed as an efficient solid support to host a nitrogen (N) and sulfur (S) coordinated ruthenium single atom (RuSA) catalyst, which displays superior activity toward the hydrogen evolution reaction (HER). X‐ray absorption fine structure spectroscopy and aberration corrected scanning transmission electron microscopy reveal the atomic dispersion of Ru on the Ti3C2Tx MXene support and the successful coordination of RuSA with the N and S species on the Ti3C2Tx MXene. The resultant RuSA‐N‐S‐Ti3C2Tx catalyst exhibits a low overpotential of 76 mV to achieve the current density of 10 mA cm−2. Furthermore, it is shown that integrating the RuSA‐N‐S‐Ti3C2Tx catalyst on n+np+‐Si photocathode enables photoelectrochemical hydrogen production with exceptionally high photocurrent density of 37.6 mA cm−2 that is higher than the reported precious Pt and other noble metals catalysts coupled to Si photocathodes. Density functional theory calculations suggest that RuSA coordinated with N and S sites on the Ti3C2Tx MXene support is the origin of this enhanced HER activity. This work would extend the possibility of using the MXene family as a solid support for the rational design of various single atom catalysts.

Etching‐Doping Sedimentation Equilibrium Strategy: Accelerating Kinetics on Hollow Rh‐Doped CoFe‐Layered Double Hydroxides for Water Splitting

“…Considering these results, the reaction process driven by Rh doped CoFe-ZLDH follows the Volmer-Heyrovsky mechanism to achieve a rapidly increasing hydrogen evolution rate under the application of voltage. As shown in Figure 3c and Table S2 in the Supporting Information, Rh-doped CoFe-ZLDH outperforms many other previously reported state-of-art HER electrocatalysts, such as Rh 2 P, [41] L-Ag, [42] single atomic Co supported on phosphorized carbon nitride nanosheets (Co 1 /PCN), [43] NiMoO x -Ni(OH) 2 /NF, [44] interface catalyst consisting of atomic cobalt array covalently bound to distorted 1T MoS 2 nanosheets (SA Co-D 1T MoS 2 ), [45] Pt clusters in hollow mesoporous carbon spheres (Pt 5 /HMCS), [46] Ni-Fe nanoparticle (Ni-Fe NF), [39] oxygen vacancy enrich CoFe 2 O 4 (r-CFO), [47] CoFeP TAPs/Ni, [48] nickel-molybdenum-nitride nanoplates on carbon fiber cloth (Ni-Mo-N/CFC), [40] Ru SA -N-S-Ti 3 C 2 T x , [9] W-CoP NAs-CC, [49] MoP@NCHs-900, [50] Co 9 S 8 @C, [51] and Co 0.31 Mo 1.69 C/MXene/NC. [52] The cyclic voltammetry (CV) method was utilized to calculate the electrochemical double-layer capacitance (C dl ) to reflect the electrochemical active area (ECSA).…”

Structural Regulation and Support Coupling Effect of Single‐Atom Catalysts for Heterogeneous Catalysis

“…By utilizing the N and S surface terminations on titanium carbide (Ti 3 C 2 T x ) MXene support, He and co-workers successfully dispersed the Ru single atoms (Ru SAs) on the Ti 3 C 2 T x support via the formation of RuN and RuS covalent bonds (Ru SA -N-S-Ti 3 C 2 T x ). [108] As a result, the active Ru SAs strongly interacted with the Ti 3 C 2 T x support can deliver a small overpotential (76 mV at 10 mA cm −2 ) and high TOF (1.50 H 2 s −1 at 200 mV) for HER under acidic conditions (Figure 6f,g). Furthermore, by integrating the as-prepared Ru SACs on the n + np + -Si photocathode, it enables photo-electrochemical hydrogen generation with large photocurrent density of 37.6 mA cm −2 higher than the most of reported precious-based catalysts.…”

“…Aside from the intrinsic defects in the surface of metal compounds, the functional groups (e.g., OH, N-containing and S-containing groups) can also trap atomically dispersed metal sites and play crucial roles in modulating the catalytic properties of SACs. [20,28,107,108] Zheng and co-workers employed a photochemical strategy to prepare an ultrastable atomically dispersed Pd 1 /TiO 2 catalyst consisting of 1.5% Pd loading on ethylene glycolate (EG) modified ultrathin TiO 2 nanosheets. [20] It was attributed to the ultraviolet light-generated EG radicals on TiO 2 nanosheets that facilitated the removal of Cl − ligands in Pd precursors and stabilized the Pd atoms by forming PdO bonds (Figure 6e).…”

Recent Progress in MXene‐Based Materials: Potential High‐Performance Electrocatalysts

“…Ramalingam et al [59] prepared a novel catalyst by using titanium carbide (Ti 3 C 2 T x ) MXene as an effective solid support to host a nitrogen (N) and sulfur (S) coordinated ruthenium single atom (Ru SA ). The obtained Ru SA -N-S-Ti 3 C 2 T x is an efficient and stable HER electrocatalyst, which exhibits a low overpotential of 76 mV, enabling a current density of 10 mA cm −2 .…”