Unraveling the Function of Metal–Amorphous Support Interactions in Single‐Atom Electrocatalytic Hydrogen Evolution

Abstract

Amorphization of the support in single‐atom catalysts is a less researched concept for promoting catalytic kinetics through modulating the metal–support interaction (MSI). We modeled single‐atom ruthenium (RuSAs) supported on amorphous cobalt/nickel (oxy)hydroxide (Ru‐a‐CoNi) to explore the favorable MSI between RuSAs and the amorphous skeleton for the alkaline hydrogen evolution reaction (HER). Differing from the usual crystal counterpart (Ru‐c‐CoNi), the electrons on RuSAs are facilitated to exchange among local configurations (Ru‐O‐Co/Ni) of Ru‐a‐CoNi since the flexibly amorphous configuration induces the possible d–d electron transfer and medium‐to‐long range p–π orbital coupling, further intensifying the MSI. This embodies Ru‐a‐CoNi with enhanced water dissociation, alleviated oxophilicity, and rapid hydrogen migration, which results in superior durability and HER activity of Ru‐a‐CoNi, wherein only 15 mV can deliver 10 mA cm−2, significantly lower than the 58 mV required by Ru‐c‐CoNi.

Ru–Co Pair Sites Catalyst Boosts the Energetics for the Oxygen Evolution Reaction

“…This suggests that additional electrons in Co atoms transfer to Ru sites, which is probably related to the lower electronegativity of Co than Ru [17] . Similarly, the positive shifting binding energy of Co 2p 3/2 and Co 2p 1/2 in the high‐resolution X‐ray photoelectron spectroscopy (XPS) of Co 2p (Figure S17) confirms the slightly decreased Co 3d electron density and enhanced d ‐band holes upon Ru incorporation [18] . The positive shift of O 1s further verifies the enhanced metal‐oxygen covalency with the presence of Ru (Figure S18).…”

“…[17] Similarly, the positive shifting binding energy of Co 2p 3/2 and Co 2p 1/2 in the high-resolution X-ray photoelectron spectroscopy (XPS) of Co 2p (Figure S17) confirms the slightly decreased Co 3d electron density and enhanced d-band holes upon Ru incorporation. [18] The positive shift of O 1s further verifies the enhanced metal-oxygen covalency with the presence of Ru (Figure S18). The Fourier-transformed(FT) Co K-edge EXAFS of RuÀ Co/ELCO (Figure 2h) shows a prominent peak at ~1.5 Å, which can be assigned to the CoÀ O coordination in the first shell, and another main peak at ~2.5 Å derived from the CoÀ Co/Ru contribution in the second shell.…”

Green Electrosynthesis of 5,5′‐Azotetrazolate Energetic Materials Plus Energy‐Efficient Hydrogen Production Using Ruthenium Single‐Atom Catalysts

“…Moreover, the Se sites exhibited the largest energy barrier (3.64 eV) among all the adsorption sites, indicating that the Ru sites in MoSe 2 /Ru SA were the main active sites for achieving the lower energy barrier of the Volmer step, which is consistent with the experimental results. [ 51 ] According to the above discussion, we proposed a synergetic effect of the alkaline HER mechanism in MoSe 2 /Ru SAs, as shown in Figure 6h. The introduction of Ru SAs lowered the energy barrier of water dissociation, forming a reactive H* intermediate, which then combined with another water molecule and desorbed H 2 on the adjacent Se sites of MoSe 2 through the Heyrovsky step.…”

“…[ 44 ] The ε d of Ru atoms in MoSe 2 /Ru NC was higher than that in MoSe 2 /Ru SA (−2.274 vs −3.578 eV), indicating a weakened affinity toward hydrogen intermediates (H*) on the Ru SA site of MoSe 2 /Ru SA. [ 51 ] In addition, the p ‐orbital density of states of Se atoms adjacent to Ru sites for MoSe 2 /Ru NC possessed more filled p ‐states than that for MoSe 2 /Ru SA (Figure 6e). Therefore, the adsorption of H* on the Se site near Ru would be weaker for MoSe 2 /Ru NC than for MoSe 2 /Ru SA.…”

Optimizing Atomically Dispersed Metal Electrocatalysts for Hydrogen Evolution: Chemical Coordination Effect and Electronic Metal Support Interaction

“…[69] Heteroatomic doping provides more anchor points for fixing metal atoms through MSI, which has aroused great research interest. In carbon-based supports, the control of doped heteroatoms such as N, [27] P, [70] S, [71] O, [72] or B [73] provides a huge space for regulating the coordination environment of single atom sites in functionalized carbon materials. [70,73] For the researches of M-N-C structure, the control and activity comparison of the coordination number and coordination structure of M-N x -C y have gradually become research hotspots.…”