Designing catalysts with highly active, selectivity, and stability for electrocatalytic CO₂ to formate is currently a severe challenge. Herein, we developed an electronic structure engineering on carbon nano frameworks embedded with nitrogen and sulfur asymmetrically dual-coordinated indium active sites toward the efficient electrocatalytic CO₂ reduction reaction. As expected, atomically dispersed In-based catalysts with In-S₁N₃ atomic interface with asymmetrically coordinated exhibited high efficiency for CO₂ reduction reaction (CO₂RR) to formate. It achieved a maximum Faradaic efficiency (FE) of 94.3% towards formate generation at −0.8 V vs. reversible hydrogen electrode (RHE), outperforming that of catalysts with In-S₂N₂ and In-N₄ atomic interface. And at a potential of −1.10 V vs. RHE, In-S₁N₃ achieves an impressive Faradaic efficiency of 93.7% in flow cell. The catalytic performance of In-S₁N₃ sites was confirmed to be enhanced through in-situ X-ray absorption near-edge structure (XANES) measurements under electrochemical conditions. Our discovery provides the guidance for performance regulation of main group metal catalysts toward CO₂RR at atomic scale.

Tandem catalysis, capable of decoupling individual steps, provides a feasible way to build a high-efficiency CO₂ electro-conversion system for multicarbons (C₂₊). The construction of electrocatalytic materials is one of focusing issues. Herein, we fabricated a single atom involved multivalent oxide-derived Cu composite material and found it inclined to reconstruct into oxygen-deficient multiphase Cu based species hybridized with monatomic Ni on N doped C matrix. In this prototype, rapid CO generation and C−C coupling are successively achieved on NiN₄ sites and surface amorphized Cu species with defects, resembling a micro-production line. In this way, the in situ formed tandem catalyst exhibited a high Faradaic efficiency (FE) of ~ 78% for C₂₊ products along with satisfactory durability over 50 h. Particularly, the reconstruction-induced amorphous layer with abundant asymmetric sites should be favorable to improve the ethanol selectivity (FE: 63%), which is about 10 times higher than that of the non-tandem Cu-based contrast material. This work offers a new approach for manipulating tandem catalyst systems towards enhancing C₂₊ products.

Single atom catalysts (SACs) have attracted great attention, yet the quest for highly-efficient catalysts is driven by the current obstacles of ambiguous structure-performance relationship. Here, we report a nature keratin-based Fe-S₁N₃ SACs with ultrathin two-dimensional (2D) porous carbon nanosheets structure, by controlling the active center through the precise coordination of sulfur and nitrogen. Compared with natural silk-based Fe-N₄ catalyst, the Fe-S₁N₃ SACs exhibit excellent Fenton-like oxidation degradation ability. X-ray absorption fine structure (XAFS) and electron paramagnetic resonance (EPR) results confirm that S doping is conducive to electron transfer, to accurately generate ·OH with high oxidative degradation capacity at the active site. Therefore, the optimized Fe-S₁N₃ catalyst showed higher oxidation degradation activity for organic pollutant substrates (methylene blue (MB), Rhodamine B (RhB) and phenol), significantly superior to Fe-N₄ samples. This work is devoted to the treatment and application of natural fibers, which provides a novel method for the synthesis of SACs and the regulation of atomic coordination environment.