Exploring earth-abundant electrocatalysts
with Pt-like performance
toward alkaline hydrogen evolution reaction (HER) is extremely desirable
for the hydrogen economy but remains challenging. Herein, density
functional theory (DFT) predictions reveal that the electronic structure
and localized charge density at the heterointerface of NiP2–FeP2 can be significantly modulated upon coupling
with metallic Cu, resulting in optimized proton adsorption energy
and reduced barrier for water dissociation, synergistically boosting
alkaline HER. Motivated by theoretical predictions, we developed a
facile strategy to fabricate interface-rich NiP2–FeP2 coupled with Cu nanowires (CuNW) grown on Cu foam
(NiP2–FeP2/CuNW/Cuf). Benefiting from the superior intrinsic activity, conductivity,
and copious active sites, the obtained catalyst exhibited exceptional
alkaline HER activity requiring a low overpotential of 23.6 mV at
−10 mA/cm2, surpassing the state-of-the-art Pt.
Additionally, a full electrolyzer required a cell voltage of 1.42/1.4
V at 10 mA/cm2 in alkaline water/seawater with promising
stability. This work highlights a design principle for advanced HER
catalysts and beyond.
Single-atom-catalysts (SACs) afford a fascinating activity with respect to other nanomaterials for hydrogen evolution reaction (HER), yet the simplicity of single-atom center limits its further modification and utilization. Obtaining bimetallic single-atom-dimer (SAD) structures can reform the electronic structure of SACs with added atomic-level synergistic effect, further improving HER kinetics beyond SACs. However, the synthesis and identification of such SAD structure remains conceptually challenging. Herein, systematic first-principle screening reveals that the synergistic interaction at the NiCo-SAD atomic interface can upshift the d-band center, thereby, facilitate rapid water-dissociation and optimal proton adsorption, accelerating alkaline/acidic HER kinetics. Inspired by theoretical predictions, we develop a facile strategy to obtain NiCo-SAD on N-doped carbon (NiCo-SAD-NC) via in-situ trapping of metal ions followed by pyrolysis with precisely controlled N-moieties. X-ray absorption spectroscopy indicates the emergence of Ni-Co coordination at the atomic-level. The obtained NiCo-SAD-NC exhibits exceptional pH-universal HER-activity, demanding only 54.7 and 61 mV overpotentials at −10 mA cm−2 in acidic and alkaline media, respectively. This work provides a facile synthetic strategy for SAD catalysts and sheds light on the fundamentals of structure-activity relationships for future applications.
Seawater is the most plentiful natural resource we have on earth and new research looking for the alternative to the freshwater as seawater for hydrogen production by electrolysis. However, selective...
Single‐atom catalysts (SACs) have become the forefront of energy conversion studies, but unfortunately, the origin of their activity and the interpretation of the synchrotron spectrograms of these materials remain ambiguous. Here, systematic density functional theory computations reveal that the edge sites—zigzag and armchair—are responsible for the activity of the graphene‐based Co (cobalt) SACs toward hydrogen evolution reaction (HER). Then, edge‐rich (E)‐Co single atoms (SAs) were rationally synthesized guided by theoretical results. Supervised learning techniques are applied to interpret the measured synchrotron spectrum of E‐Co SAs. The obtained local environments of Co SAs, 65.49% of Co‐4N‐plane, 13.64% in Co‐2N‐armchair, and 20.86% in Co‐2N‐zigzag, are consistent with Athena fitting. Remarkably, E‐Co SAs show even better HER electrocatalytic performance than commercial Pt/C at high current density. Using the joint effort of theoretical modeling, thorough characterization of the catalysts aided by supervised learning, and catalytic performance evaluations, this study not only uncovers the activity origin of Co SACs for HER but also lays the cornerstone for the rational design and structural analysis of nanocatalysts.
Designing an efficient oxygen evolution reaction (OER) electrocatalysts based on single-atom catalysts is a highly promising option for cost-effective alkaline water electrolyzers. However, the instability of the OOH* intermediate and...
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.
Single-atom-catalysts (SACs) have recently gained significant attention in energy conversion/storage application, while the low-loading amount due to their easy-to-migrate tendency poses a major bottleneck. For energy-saving H2 generation, replacing sluggish...
Recently, many research studies have been focused on anion or cation substitution into the lattice of pyrite-type cobalt disulfide (CoS 2 ) for enhancing the hydrogen evolution reaction (HER) performance. Nonetheless, finding the correct pair of anion−cation dual substitution with added synergistic effect for boosting pH-universal HER activity remains an ongoing challenge. Additionally, a generalized activity descriptor and the HER mechanism in alkaline media remain elusive. Herein, to elucidate the HER mechanism and obtain the suitable anion−cation pair, we investigated the codoping of metal cations (Ti/V/Cr/Mn/Fe) and phosphorus anions into the CoS 2 moiety. Our theoretical prediction revealed that Ti and P codoping into CoS 2 exhibits superior HER performance at both pH 0 and 14, which is ascribed to the weak hydrogen binding energy in acid and fast water dissociation kinetics in alkaline media, thereby promoting HER. Remarkably, a follow-up experiment confirmed that Ti-CoSP showed astonishing HER activity inducing low overpotentials of 44 and 132 mV at −10 mA cm −2 in acidic and alkaline media, respectively, with superior stability for 40 h.
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