To understand the molecular-level reaction mechanism and crucial activity-limiting factors of the NH3-SCR process catalyzed by MnO2-based oxide to eliminate NO (4NH3 + 4NO + O2 →4N2 + 6H2O) at middle–low temperature, a systematic computational investigation is performed on β-MnO2(110) by first-principles calculations together with microkinetic analysis. Herein, the favored reaction pathways are unveiled. (i) NH3 tends to adsorb at the unsaturated Lewis acid Mn5c site on MnO2(110) and then partially dissociates into NH2* (assisted by the surface lattice Obri) at the steady state, triggering the subsequent reactions. (ii) Interestingly, NO, either in the gas phase or at the adsorbed state, can readily react with NH2* to give the key intermediate NH2NO, with the former (i.e., the Eley–Rideal pathway) being slightly more kinetically preferred. (iii) NH2NO conversion is identified to proceed easily to N2 through the dehydrogenation/hydrogenation processes NH2NO → NHNO → NHNOH → N2 + H2O. (iv) The removal of the accumulated surface H into H2O, assisted by O2, is relatively difficult, which preferentially occurs via the Mars–van Krevelen mechanism. Quantitatively, a kinetic analysis is conducted to deal with such a complex reaction network, revealing that the rate-limiting steps are NH2* + NO­(g) → NH2NO* and ObriH + O2# →OOH# + Obri. Moreover, a sensitivity analysis shows that the adsorption strengths of H on Obri and O2 in the Obri vacancy (Ovac) are two main activity-determining factors for the overall NH3-SCR on MnO2(110); notably, it is further found that the Ovac formation energy correlates well with both factors and can thus serve as a unified activity descriptor. In addition, the effects of catalyst surface environment under the reaction conditions on the NH3-SCR activity and selectivity are discussed. In comparison with the pristine state of MnO2(110), both the overall activity and N2 selectivity (versus N2O) would be interestingly enhanced when it arrives at the kinetically steady state that the surface Obri are largely covered by H. These results could provide a consolidated theoretical basis for understanding and optimizing MnO2 catalysts for the NH3-SCR process.

Identification of the active centers dynamically stable under the reaction condition is of paramount importance but challenging because of the limited knowledge of steady-state chemistry on catalysts at the atomic level. Herein, focusing on the Fe2O3 catalyst for the selective catalytic reduction of NO with NH3 (NH3-SCR) as a model system, we reveal quantitatively the self-evolving Fe3+@Fe2+ (∼1:1) double-centers under the in-situ condition by the first-principles microkinetic simulations, which enables the accurate prediction of the optimal industry operating temperature (590 K). The cooperation of this double-center achieves the self-optimization of catalytic activity and rationalizes the intrinsic origin of Fe2O3 catalyzing NH3-SCR at middle-high temperatures instead of high temperatures. Our findings demonstrate the atomic-level self-evolution of active sites and the dynamically adjusted activity variation of the catalyst under the in-situ condition during the reaction process and provide insights into the reaction mechanism and catalyst optimization.

Improving metal loading and controlling the coordination environment is nontrivial and challenging for single‐atom catalysts (SACs), which have the greatest atomic efficiency and largest number of interface sites. In this study, a matching bidentate ligand (MBL) anchoring strategy is designed for the construction of CuN4 SACs with tunable coordination environments (Cu loading range from 0.4 to15.4 wt.%). The obtained Cu SA/ZIF and Cu SA/ZIF* (0.4 wt.%) (ZIF and ZIF* = Zeolitic imidazolate framework with Matching bidentate N‐ligands) nanocomposites exhibit superior performance in homo‐coupling of phenyl acetylene under light irradiation (TON = 580, selectivity > 99%), which is 22 times higher than that of Cu SA/NC‐800 (NC = N‐doped porous carbon). Experiments and density functional theory calculations confirmed that the specific Cu five‐membered ring formed using the MBL anchoring strategy is the key to the immobilization of isolated Cu atoms. This strategy provides a basis for the construction of M SA/MOF, which has the potential to narrow the gap between experimental and theoretical catalysis, as further confirmed by the successful preparation of Fe SA/ZIF and Ni SA/ZIF.

Regulation of Hybrid Materials of Ministry of Education, Bimetallic nanoclusters with synergistic effect exhibit better stability and activity than monometallic nanoclusters in catalytic applications. However, the large number of ligands on the surface of nanoclusters obscure the active sites, thus reducing the catalytic activity. Here, AuCu24/AC−X (X=0, 200, 300, 500, 800) catalysts were fabricated by removing the partial ligands on the surface of AuCu24H22((p‐FPh)3P)12 nanoclusters (short for AuCu24 NCs), and investigated the influence of calcination temperature on catalytic performance of AuCu24/AC in homocoupling and heterocoupling of terminal alkynes. The results showed that the catalytic activity of AuCu24/AC−X exhibited a volcanic trend with the increase of X (heat treatment temperature) and the content of Cu2+ also changed with the increase of X. Compared with Au25/AC‐200 and Cu25/AC‐200 catalysts, the AuCu24/AC‐200 bimetallic catalyst showed the highest catalytic activity in homocoupling and heterocoupling of terminal alkynes under mild conditions with TOF values reaching 478.7 h−1 and 114.1 h−1 respectively, which are higher than most reported catalysts. This work provides a research idea for the design of bimetallic nanoclusters with superior performance.