The most active Cu facet for low-temperature water gas shift reaction

Abstract

Identification of the active site is important in developing rational design strategies for solid catalysts but is seriously blocked by their structural complexity. Here, we use uniform Cu nanocrystals synthesized by a morphology-preserved reduction of corresponding uniform Cu2O nanocrystals in order to identify the most active Cu facet for low-temperature water gas shift (WGS) reaction. Cu cubes enclosed with {100} facets are very active in catalyzing the WGS reaction up to 548 K while Cu octahedra enclosed with {111} facets are inactive. The Cu–Cu suboxide (CuxO, x ≥ 10) interface of Cu(100) surface is the active site on which all elementary surface reactions within the catalytic cycle proceed smoothly. However, the formate intermediate was found stable at the Cu–CuxO interface of Cu(111) surface with consequent accumulation and poisoning of the surface at low temperatures. Thereafter, Cu cubes-supported ZnO catalysts are successfully developed with extremely high activity in low-temperature WGS reaction.

Porous CuxCoyS Supraparticles for In Vivo Telomerase Imaging and Reactive Oxygen Species Generation

“…By investigating differences between the three types of SPs, we suggest that the enhanced ROS production by Cu x Co y S SPs could be attributed to the accessible redox couple that may be formed between the metal ions with different covalent state . Moreover, it is possible that the porosity of the SPs could also enhance their catalytic ability (for the extracellular detection of ROS production) and therefore produce ROS more efficiently due to the enhanced surface area, the creation of more reactive sites, and by reducing charge recombination …”

Facet Sensitivity of Capping Ligand‐Free Ag Crystals in CO2 Electrochemical Reduction to CO

“…The observed morphology‐preserved reduction of Ag 2 O NCs into Ag NCs can be attributed to the cubic phase structures of both Ag 2 O and Ag, the not too large difference between the lattice constants of Ag 2 O (a=473.6 pm) and Ag (a=408.6 pm), the large sizes of Ag 2 O NCs, and the low reduction temperature. Such a morphology‐preserved transformation between oxide and metal crystals greatly expands the capability to synthesize crystals with uniform morphologies . However, the lattice mismatch between Ag 2 O and Ag do affect the surfaces of acquired Ag crystals.…”

Solar‐Driven Water–Gas Shift Reaction over CuOx/Al2O3 with 1.1 % of Light‐to‐Energy Storage

“…The pre‐catalyst contained CuO with a little amount of Cu 2 O (as presented in Figure S3 and Figure S4A). After light‐driven WGS reaction, the Cu‐based active phase transformed into Cu and Cu 2 O (as shown in Figure S3 and Figure S4B,C; the presence of Cu 2+ can be ascribed to the oxidization of nano‐catalyst exposed in air), which is in accordance with the thermal catalysis . Thereby, the catalyst is denoted as CuO x /Al 2 O 3 .…”

“…The effect of interfacial oxygen vacancy of Cu‐Cu 2 O in CuO x /Al 2 O 3 catalyst on WGS reaction was reported by Zhang and co‐workers . Figure A shows the schematic illustration of two important processes of the oxidation of CO and the reduction of water in thermal catalytic WGS reaction.…”