Engineering Single‐Atom Cobalt Catalysts toward Improved Electrocatalysis

Abstract

The development of cost-effective catalysts to replace noble metal is attracting increasing interests in many fields of catalysis and energy, and intensive efforts are focused on the integration of transition-metal sites in carbon as noble-metal-free candidates. Recently, the discovery of single-atom dispersed catalyst (SAC) provides a new frontier in heterogeneous catalysis. However, the electrocatalytic application of SAC is still subject to several theoretical and experimental limitations. Further advances depend on a better design of SAC through optimizing its interaction with adsorbates during catalysis. Here, distinctive from previous studies, favorable 3d electronic occupation and enhanced metal-adsorbates interactions in single-atom centers via the construction of nonplanar coordination is achieved, which is confirmed by advanced X-ray spectroscopic and electrochemical studies. The as-designed atomically dispersed cobalt sites within nonplanar coordination show significantly improved catalytic activity and selectivity toward the oxygen reduction reaction, approaching the benchmark Pt-based catalysts. More importantly, the illustration of the active sites in SAC indicates metal-natured catalytic sites and a media-dependent catalytic pathway. Achieving structural and electronic engineering on SAC that promotes its catalytic performances provides a paradigm to bridge the gap between single-atom catalysts design and electrocatalytic applications.

The Multifaceted Reactivity of Single‐Atom Heterogeneous Catalysts

“…[28,54,121] However,s urpassing the efficiencyo fP t/C is challenging since the reaction proceeds by a2e À pathway and produces less electricity than the alternative 4e À pathway.On the other hand, this presents an efficient route for the H 2 O 2 synthesis,i nw hich case higher selectivity is expected upon complete elimination of NPs and clusters.T he improved performance of aPt 1 /TiC catalyst than Pt 1 /TiN indicated that the support can strongly influence the performance. [122][123][124][125][126][127] Interesting prospects to tune the mechanism have been reported in the oxidations of methanol, ethanol, and formic acid. [122][123][124][125][126][127] Interesting prospects to tune the mechanism have been reported in the oxidations of methanol, ethanol, and formic acid.…”

The Proportion of Fe‐NX, N Doping Species and Fe3C to Oxygen Catalytic Activity in Core‐Shell Fe‐N/C Electrocatalyst

“…A control experiment was carried out to further support the above verdict. The Fe−N x species are benefit for ORR reaction, and the Fe−N x species in Fe 3 C@ N ‐CSs is blocked by SCN − ions . As it can be seen in Figure S15, a small activity deterioration of Fe 3 C@ N ‐CSs is evidenced.…”

N,P Co‐Coordinated Manganese Atoms in Mesoporous Carbon for Electrochemical Oxygen Reduction

“…Therefore, numerous carbon‐based nanomaterials have been developed to replace the Pt based composites . Among them, the nitrogen species coordinated first‐row transition metal (e.g., Co, Ni, and Fe) atoms in carbons (M–N–C) are widely considered as promising electrocatalysts for ORR . The M–N–C materials are usually recognized as single‐atom catalysts (SACs), since isolated N‐bonded metals atoms are embedded in carbons.…”