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Reverse water gas shift (RWGS) reaction is an attractive approach to convert CO2 with renewable H2 to produce CO. However, this reaction is always accompanied by undesirable methanation reaction lowering the CO selectivity, particularly, at low reaction temperature and on Ni catalysts. Herein, a strategy of deposition of inert Ag on the surface of Ni to block methanation reaction during RWGS for selective conversion of CO2 toward CO was reported. Characterizations showed that in contrast to formation of bulk Ni−Ag alloy, both Ag particle and highly dispersed Ag are direct contacting with Ni particle. Surface Ag modifies the property of Ni geometrically and electronically, resulting in reduced accessible surface Ni sites and Ni ensemble size, as well as electron transfer from Ni to Ag. Consequently, both the amount and strength of CO adsorption are reduced, which facilitates CO desorption and reduces CO methanation activity. The Ag modification tunes Ni/SiO2 from selective methanation to selective RWGS, with 100 % CO selectivity on Ni‐0.3 Ag/SiO2 (Ag/Ni=0.3) at 400 °C with gas hourly space velocity (GHSV) >300 L g−1 h−1 and CO selectivity is >80.7 % even at a low GHSV of 15 L g−1 h−1. Moreover, the Ni‐0.3 Ag/SiO2 appears to be very stable for RWGS reaction. [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]

There is no doubt that hydrogen energy can play significant role in promoting the development and progress of modern society. The utilization of hydrogen energy has developed rapidly, but it is far from the requirement of human. Therefore, it is very urgent to develop methodologies and technologies for efficient hydrogen production, especially high activity and durable electrocatalysts. Here a bimetallic oxide cluster on heterostructure of vanadium ruthenium oxides/graphdiyne (VRuOx/GDY) is reported. The unique acetylene‐rich structure of graphdiyne achieves outstanding characteristics of electrocatalyst: i) controlled preparation of catalysts for achieving multiple‐metal clusters; ii) regulation of catalyst composition and morphology for synthesizing high‐performance catalysts; iii) highly active and durable hydrogen evolution reaction (HER) properties. The optimal porous electrocatalyst (VRu0.027Ox/GDY) can deliver 10 mA cm−2 at low overpotentials of 13 and 12 mV together with robust long‐term stability in alkaline and neutral media, respectively, which are much smaller than Pt/C. The results reveal that the synergism of different components can efficiently facilitate the electron/mass transport properties, reduce the energy barrier, and increase the active site number for high catalytic performances. [ABSTRACT FROM AUTHOR]

Development of novel catalysts for nitrogen reduction at ambient pressures and temperatures with ultrahigh ammonia (NH3) yield and selectivity is challenging. In this work, an atomic catalyst with separated Pd atoms on graphdiyne (Pd-GDY) was synthesized, which shows fascinating electrocatalytic properties for nitrogen reduction. The catalyst has the highest average NH3 yield of 4.45 ± 0.30 mgNH3 mgPd−1 h−1, almost tens of orders larger than for previously reported catalysts, and 100% reaction selectivity in neutral media. Pd-GDY exhibits almost no decreases in NH3 yield and Faradaic efficiency. Density functional theory calculations show that the reaction pathway prefers to perform at the (Pd, C1, C2) active area because of the strongly coupled (Pd, C1, C2), which elevates the selectivity via enhanced electron transfer. By adjusting the p–d coupling accurately, reduction of self-activated nitrogen is promoted by anchoring atom selection, and side effects are minimized. [ABSTRACT FROM AUTHOR]

A freestanding 3D graphdiyne–cobalt nitride (GDY/Co2N) with a highly active and selective interface is fabricated for the electrochemical nitrogen reduction reaction (ECNRR). Density function theory calculations reveal that the interface‐bonded GDY contributes an unique p‐electronic character to optimally modify the Co‐N compound surface bonding, which generates as‐observed superior electronic activity for NRR catalysis at the interface region. Experimentally, at atmospheric pressure and room temperature, the electrocatalyst creates a new record of ammonia yield rate (YNH3) and Faradaic efficiency (FE) of 219.72 μg h−1 mgcat.−1 and 58.60 %, respectively, in acidic conditions, higher than reported electrocatalysts. Such a catalyst is promising to generate new concepts, new knowledge, and new phenomena in electrocatalytic research, driving rapid development in the field of electrocatalysis. [ABSTRACT FROM AUTHOR]

A highly efficient bifunctional metal‐free catalyst was prepared by growth of three‐dimensional porous fluorographdiyne networks on carbon cloth (p‐FGDY/CC). Our experiments and density functional theory (DFT) calculations show the 3D p‐FGDY/CC network is highly active and it is a high potential metal‐free catalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), as well as overall water splitting (OWS) under both acidic and alkaline conditions. The experimental and theoretical results show very good consistency; for example, in the HER process, p‐FGDY/CC exhibits small overpotentials of 82 and 92 mV to achieve 10 mA cm−2 under alkaline and acidic conditions, respectively. This ensures an even higher selectivity for the adsorption/desorption of various O/H intermediate species. The essential key promotion accomplishes a bifunctional H2O redox performance application under pH‐universal electrochemical conditions. [ABSTRACT FROM AUTHOR]

A highly efficient bifunctional metal‐free catalyst was prepared by growth of three‐dimensional porous fluorographdiyne networks on carbon cloth (p‐FGDY/CC). Our experiments and density functional theory (DFT) calculations show the 3D p‐FGDY/CC network is highly active and it is a high potential metal‐free catalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), as well as overall water splitting (OWS) under both acidic and alkaline conditions. The experimental and theoretical results show very good consistency; for example, in the HER process, p‐FGDY/CC exhibits small overpotentials of 82 and 92 mV to achieve 10 mA cm−2 under alkaline and acidic conditions, respectively. This ensures an even higher selectivity for the adsorption/desorption of various O/H intermediate species. The essential key promotion accomplishes a bifunctional H2O redox performance application under pH‐universal electrochemical conditions. [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]