Electrocatalytic urea synthesis emerged as the promising alternative of Haber–Bosch process and industrial urea synthetic protocol. Here, we report that a diatomic catalyst with bonded Fe–Ni pairs can significantly improve the efficiency of electrochemical urea synthesis. Compared with isolated diatomic and single-atom catalysts, the bonded Fe–Ni pairs act as the efficient sites for coordinated adsorption and activation of multiple reactants, enhancing the crucial C–N coupling thermodynamically and kinetically. The performance for urea synthesis up to an order of magnitude higher than those of single-atom and isolated diatomic electrocatalysts, a high urea yield rate of 20.2 mmol h−1 g−1 with corresponding Faradaic efficiency of 17.8% has been successfully achieved. A total Faradaic efficiency of about 100% for the formation of value-added urea, CO, and NH3 was realized. This work presents an insight into synergistic catalysis towards sustainable urea synthesis via identifying and tailoring the atomic site configurations.
Metal oxides are archetypal CO2 reduction reaction electrocatalysts, yet inevitable self-reduction will enhance competitive hydrogen evolution and lower the CO2 electroreduction selectivity. Herein, we propose a tangible superlattice model of alternating metal oxides and selenide sublayers in which electrons are rapidly exported through the conductive metal selenide layer to protect the active oxide layer from self-reduction. Taking BiCuSeO superlattices as a proof-of-concept, a comprehensive characterization reveals that the active [Bi2O2]2+ sublayers retain oxidation states rather than their self-reduced Bi metal during CO2 electroreduction because of the rapid electron transfer through the conductive [Cu2Se2]2- sublayer. Theoretical calculations uncover the high activity over [Bi2O2]2+ sublayers due to the overlaps between the Bi p orbitals and O p orbitals in the OCHO* intermediate, thus achieving over 90% formate selectivity in a wide potential range from −0.4 to −1.1 V. This work broadens the studying and improving of the CO2 electroreduction properties of metal oxide systems.
Formate and CO are competing products in the two-electron CO2 reduction reaction (2e CO2RR), and they are produced via *OCHO and *COOH intermediates, respectively. However, the factors governing CO/formate selectivity...
A closely packed hybrid electrocatalyst Pt1.5Ni1−x/Ni–N–C was engineered by a gas-promoted dealloying process, ensuring the relay catalysis of the reaction intermediates at Pt alloy and Ni single sites, thus achieving high performance in PEMFCs.
Achieving efficient bifunctional oxygen reduction and evolution reactions (ORR/OER) on non-noble metal catalysts is desirable but remains a significant challenge. Herein, inspired by the experimentally synthesized (phen 2 N 2 )FeCl molecule, a stable 2D organometallic framework, namely (phen 2 N 2 )FeCl monolayer, is proposed as a qualified candidate by means of constant-potential first-principles computations. Unlike most 2D organometallic frameworks that feature pyrrolic coordination, the (phen 2 N 2 ) FeCl monolayer exhibits a pyridinic-type FeN 4 ligation environment. The unique structure of the monolayer enables a high single-atom Fe loading in a heterogeneous system, superior to the typical FeNC materials. Constant-potential energy analysis and microkinetic modeling demonstrate that the monolayer holds great potential for facilitating bifunctional ORR/OER in both the acidic and alkaline conditions, showing theoretical activity higher than the FeNC materials, (phen 2 N 2 )FeCl molecule, and Pt/IrO 2 . Moreover, (phen 2 N 2 )MCl monolayers (M = Mn, Co, and Ni) are explored, and the (phen 2 N 2 )MnCl monolayer is also identified to have excellent bifunctional activity. This study highlights the rational design of local coordination environments for boosting the electrocatalytic performance of 2D organometallic frameworks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.