Cu/CuO_x In-Plane Heterostructured Nanosheet Arrays with Rich Oxygen Vacancies Enhance Nitrate Electroreduction to Ammonia

Abstract

The artificial ammonia synthesis via electrochemical nitrate reduction has met increasing research interest, but it is still necessary to develop advanced catalysts with high nitrate-to-ammonia capability. Herein, we propose and demonstrate a one-step method to construct binder-free Cu foam-supported oxygen vacancy-rich Cu/CuO x in-plane heterostructured nanosheet arrays (Cu/CuO x /CF). In addition to exposing ample active sites, the two-dimensional nanosheet morphology greatly facilitates the mass/charge-transfer process during electrocatalysis. Besides, the in-plane heterojunctions and rich oxygen vacancies induced synergistic effect can modulate the electronic structure of active sites and thus tune the adsorption properties of the reactant intermediates and inhibit the formation of undesirable byproducts, which is conducive to the further improvement of nitrate reduction activity. As a result, these advantages endow the Cu/CuO x /CF with superior performance for ammonia synthesis via nitrate electroreduction, achieving high ammonia selectivity (95.00%) and Faradaic efficiency (93.58%).

Promoting nitrate electroreduction to ammonia over A-site deficient cobalt-based perovskite oxides

“…42 Recently, some studies have shown that the introduction of oxygen vacancies in an electrocatalyst can signicantly boost its NO 3 ER activity. 25,[43][44][45][46] The main mechanism has been well recognized to be that the oxygen atoms in nitrate tend to ll the oxygen vacancies in the catalyst, which can effectively capture nitrate and promote the adsorption and reduction of nitrate, weaken the N-O bond and restrict the formation of by-products, thus improving the selectivity and efficiency of ammonia synthesis by NO 3 ER. As shown in Fig.…”

High-efficiency electroreduction of nitrite to ammonia on a Cu@TiO2 nanobelt array

“…2b) shows two strong peaks at 933.2 and 953.1 eV corresponding to Cu 2p 3/2 and Cu 2p 1/2 of Cu 0 or Cu + species, while the other peaks at 935.2 and 955.3 eV (matched with the Cu 2+ 2p 3/2 and Cu 2+ 2p 1/2 ) are mainly derived from the oxidation of metallic Cu in air. 33,34 As observed in Fig. 2c, the Ti 2p spectrum of TiO 2 can be divided into two peaks centred at 458.9 and 464.7 eV, assigned to Ti 2p 3/2 and Ti 2p 1/2 , respectively.…”

Development of copper foam-based composite catalysts for electrolysis of water and beyond

“…11a), and the 2D nanosheet arrays can offer more exposed active sites and considerably promote mass and charge transfer when combined with the 2D morphology of copper-based nanomaterials. 154 More significantly, the dual impact of heterogeneous structure and oxygen-rich vacancies enhances catalytic performance and lowers the production of byproducts. Fig.…”