Asymmetric Coordination of Single‐Atom Co Sites Achieves Efficient Dehydrogenation Catalysis

Abstract

Tuning asymmetric coordination of metal single-atom (SA) sites can provide a new opportunity for optimizing the electronic structure of catalysts to achieve efficient catalysis, however, achieving such controllable design remains a grand challenge. Herein, an asymmetrically coordinated Co-N 4 P SA site as a new catalyst system for achieving superior dehydrogenation catalysis of formic acid (HCOOH) is reported. The experimental results show that the Co atom is coordinated by four N atoms and one asymmetric P atom, forming the unique Co-N 4 P SA sites. The Co-N 4 P SA sites exhibit an impressive mass activity of 4285.6 mmol g -1 h -1 with 100% selectivity and outstanding stability for HCOOH dehydrogenation catalysis at 80 °C, which is 5.0, 25.5, and 23.1 times that of symmetrically coordinated Co-N 4 SA sites, commercial Pd/C and Pt/C, respectively. The in situ ATR-IR analysis demonstrates the mono-molecular H 2 produced mechanism over Co-N 4 P SA sites, and theoretical calculations further reveal that the asymmetric P sites not only can boost the CH bond cleavage of HCOO* by largely reducing the energy barrier but also facilitate the proton adsorption to achieve the fast generation of H 2 in Co-N 4 P SA sites. This study opens a new way for rationally designing novel SA sites to achieve efficient catalysis.

Anti‐CO Poisoning FePtRh Nanoflowers with Rh‐Rich Core and Fe‐Rich Shell Boost Methanol Oxidation Electrocatalysis

“…The asymmetric stretch vibration of CO 2 can be observed at ≈2340 cm −1 on both Fe 26 Pt 74 /C and Fe 21 Pt 66 Rh 13 /C, suggesting CO 2 is the main product of methanol oxidation. [46,47] Compared with Fe 26 Pt 74 /C, the potential of CO 2 produced on Fe 21 Pt 66 Rh 13 /C is much lower, indicating the easier completing oxidation of methanol due to the introduction of Rh atoms. In addition, two catalysts can adsorb CO* during the methanol oxidation process, producing linear-absorbed CO* (CO L ), confirmed by the appeared bipolar bands located near 2010 cm −1 (Figure S24, Supporting Information).…”

The synthesis of single-atom catalysts for heterogeneous catalysis

“…The enhanced electron back donation (Pt to CuO) by EMSIs could produce sufficiently positively charged Pt atoms that facilitated the activation of acetone at the low temperature. Ma's group 123 reported an asymmetrically coordinated Co–N 4 P single-atom site as a new catalyst system for achieving superior dehydrogenation of formic acid. The asymmetric coordination environment in Co–N 4 P increased the C-H bond cleavage of HCOO* via the reduction of the energy barrier and boosted proton adsorptions to accelerate the fast generation of H 2 in Co–N 4 P. The as-made 5.3 wt% Co–N 4 P possessed an impressive mass activity (4285.6 mmol g −1 h −1 ) with 100% selectivity and outstanding stability toward the dehydrogenation of formic acid at 80 °C, which was 5.0, 25.5, and 23.1 times that of symmetrically coordinated Co–N 4 , commercial Pd/C and Pt/C, respectively.…”

Enhanced Activity of WOx-Promoted PdNi Nanoclusters Confined by Amino-Modified KIT-6 for Dehydrogenation of Additive-Free Formic Acid

“…Hydrogen energy is considered one of the most promising solutions because of its renewability and high energy density. − However, its safe and efficient storage and release on a large scale are still the greatest challenges. Formic acid (FA, HCOOH), featured as a major liquid product of biomass processing and especially a liquid sunshine carrier, thus becomes a renewable and promising liquid organic hydrogen carrier due to its high volumetric capacity, low toxicity, low flammability, and easy storage and transportation. − To this end, formic acid should be selectively decomposed to release H 2 through the dehydrogenation route (HCOOH → H 2 + CO 2 ) rather than the dehydration pathway (HCOOH → H 2 O + CO). − The dehydrogenation of FA under ambient conditions is still heavily dependent on precious-metal catalysts, such as Pd and Au. − However, the high cost and low reserves of these noble-metal catalysts greatly hinder their wide applications. To save the cost of the catalysts, the development of non-noble-metal catalysts is attractive. − However, the catalytic performance of these catalysts is still far from ideal even at elevated temperatures, especially in the absence of additives (e.g., HCOONa).…”