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Precise regulation of the active site structure is an important means to enhance the activity and selectivity of catalysts in CO2 electroreduction. Here, we creatively introduce anionic groups, which can not only stabilize metal sites with strong coordination ability but also have rich interactions with protons at active sites to modify the electronic structure and proton transfer process of catalysts. This strategy helps to convert CO2 into fuel chemicals at low overpotentials. As a typical example, a composite catalyst, CuO/Cu−NSO4/CN, with highly dispersed Cu(II)−SO4 sites has been reported, in which CO2 electroreduction to formate occurs at a low overpotential with a high Faradaic efficiency (−0.5 V vs. RHE, FEformate=87.4 %). Pure HCOOH is produced with an energy conversion efficiency of 44.3 % at a cell voltage of 2.8 V. Theoretical modeling demonstrates that sulfate promotes CO2 transformation into a carboxyl intermediate followed by HCOOH generation, whose mechanism is significantly different from that of the traditional process via a formate intermediate for HCOOH production. [ABSTRACT FROM AUTHOR]

Exploring earth‐abundant materials for low concentration CO2 photoreduction is the key in the energy related field. Here, we demonstrated biphasic titania (anatase and rutile) derived from Ti‐based metal‐organic framework (MOF) nanoplates exhibited excellent performance in CO2 photoreduction without any co‐catalysts and sacrificial agents under ambient condition, the maximum CH4 production rate was up to 65.39 μmol g−1 h−1 with near 100 % electron selectivity as well as great stability. The activity of the optimal derivative was maintained well even in 1 % CO2 (CH4: 45.59 μmol g−1 h−1) and much better than that of commercial P25. The upgraded performance originated from the synergism between local anatase/rutile interface and numerous defective sites (Ti3+ and Ov), by promoting the separation and migration of photogenerated carriers, CO2 adsorption and activation, and H2O dissociation. Besides, a possible fast hydrodeoxygenation mechanism for methane formation was proposed according to in situ DRIFTS characterization. [ABSTRACT FROM AUTHOR]

The recent discovery of anti‐chiral edge states in magnetic semimetals linking two unequal‐frequency bulk Dirac nodes manifests a paradoxical picture in contrast to the chiral behavior in Chern insulators, implying an untapped phase may exist. Here, a unique Chern metal, exhibiting a nontrivial Chern number but without a complete bandgap is proposed, and the complete topological phase diagram in the modified Haldane model is obtained. Subsequently, the Chern metal in a 2D honeycomb‐lattice gyromagnetic photonic crystal by simultaneously breaking parity and time‐reversal symmetries with opposite and unequal magnetic biases at different sublattices is realized. For the paired complementary‐shape boundaries, such as zigzag/bearded, it is experimentally revealed that either clockwise or counter‐clockwise chiral character is switchable in Chern metals relying on different boundary choices, a remarkable property deemed as bi‐chiral edge propagation. The topological Chern metal with hidden bulk‐boundary correspondence is articulated to bridge the chiral and anti‐chiral paradox gap between Chern insulators and magnetic semimetals. These results enrich the family of Chern materials and highlight the previously untapped on‐demand control of topological edge states. [ABSTRACT FROM AUTHOR]