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Catalytic reduction of CO 2 with renewable H 2 to CO via the reverse water gas shift (RWGS) reaction is an attractive approach to recycle CO 2 and control net emission of CO 2 to atmosphere. However, low activity and high CH 4 selectivity at low temperatures limited the practical implementation of the reaction. Herein, Pt-Re/SiO 2 catalysts with varying amount of Re were prepared with co-impregnation and tested for the RWGS reaction. Characterization results indicated that the oxophilic ReO x (0 ≤ x ≤ 3.5) located in close proximity to Pt particle, modified the surface of Pt by both partial coverage and electronic interaction, resulting in the reduced number of sites for and weakened strength of CO adsorption. At 400 °C, the turnover frequency (2.30 s−1) on the optimal Pt-Re/SiO 2 catalyst (Pt/Re = 1.91) is 3.9 times higher than that on Pt/SiO 2 under differential conditions, and the apparent activation energy is lowered. In contrast to Re/SiO 2 which produces significant amount of CH 4 , the CO selectivity on Pt-Re/SiO 2 maintained > 96.2 % under integral conditions. Reaction order analysis revealed that Pt facilitates H 2 activation whereas the oxophilic ReO x enhances CO 2 adsorption and activation. The perimeter sites at the Pt/ReO x interface with a balanced hydrogenation and C-O cleavage properties synergistically improve the RWGS activity while inhibiting CH 4 production. [Display omitted] • ReO x (0 ≤ x ≤ 3.5) modified the surface of Pt by both partial coverage and electronic interaction. • ReO x modification weakened CO adsorption on Pt and enhanced CO selectivity (> 96.2 %). • TOF of RWGS on optimal Pt-Re/SiO 2 (2.30 s−1) is 3.9 times higher than that on Pt/SiO 2. • Reaction kinetic analysis revealed Pt and ReO x activate H 2 and CO 2 , respectively. • The synergy of Pt and ReO x enhanced RWGS activity and inhibited CH 4 formation. [ABSTRACT FROM AUTHOR]

An efficient way of aza-Henry reaction between isatin-derived N -Boc ketimines and α -aryl nitromethanes catalyzed by bifunctional phase transfer catalysts with a quaternary ammonium center derived from L - tert -Leucine has been developed. A series of 3-substituted 3-amino-oxindoles were constructed by this catalytic protocol in excellent yields (90–99%), with high enantioselectivities (83–95%) and diastereoselectivities (79:21–97:3). The asymmetric aza-Henry reaction of N -Boc amidosulfones and α -aryl nitromethanes were also investigated and gave the corresponding products in high to excellent yields (72–97%) with high enantioselectivities (up to 99%) and diastereoselectivities (up to >99:1). Image 1 • A series of bifunctional APT catalysts derived from L - tert -Leucine. • Excellent yields, high diastereo- and enantioselectivities (ee 83–95%; dr 79:21–97:3). • This catalyst can also catalyze aza-Henry reaction with N-Boc amidosulfones. [ABSTRACT FROM AUTHOR]

[Display omitted] • The content of pyridinic N in Co-N-C catalysts is modulated via solvent effect. • DFT calculations reveal that the synergy of pyridinic-N and CoN x significantly accelerate the ORR. • The content of pyridine N in the prepared atomically dispersed Co-N-C catalyst is up to 43.7%. • The optimal Co-N-C catalyst exhibits high ORR activity in acid media. Rational design of platinum group metal (PGM)-free catalysts, e.g., M−N−C catalysts, with well-defined structure is highly essential to replace the conventional PGM-based catalysts towards oxygen reduction reaction (ORR), which, however, is still challenging. Particularly, extra nitrogen plays an important role in the ORR performance of M−N−C but the mechanism remains unclear. In this work, a facile modulation strategy based on solvent effect is proposed to tailor nitrogen dopants in the metal organic frameworks (MOFs)-derived Co-N-C catalysts. DFT calculations reveal that the synergy of pyridinic-N and CoN x significantly accelerate the ORR. Reasonably, the optimized Co-N-C catalyst shows superior onset potential (E onset) of 0.915 V and half-wave potential (E 1/2) of 0.785 V toward ORR. This work may pave an avenue for the precise construction of active moieties in large-scale preparation of PGM-free ORR catalyst. [ABSTRACT FROM AUTHOR]