Zinc Substitution‐Induced Subtle Lattice Distortion Mediates the Active Center of Cobalt Diselenide Electrocatalysts for Enhanced Oxygen Evolution

Abstract

Doping engineering has been an important approach to boost oxygen evolution reaction (OER) activity, while investigation on the dopant‐induced modification of active sites and reaction kinetics remains incomplete. Herein, taking the cubic CoSe2 as an example, a universal strategy to synergistically achieve active sites and dynamic regulation is developed by incorporating low‐valence Zn. It is revealed that regulation by Zn can facilitate reconstruction of the surface to form active Co oxyhydroxides under OER conditions. By combining theoretical calculations and characterization by various techniques, it is shown that the incorporation of Zn into CoSe2 can cause subtle lattice distortion and strong electronic interactions, thereby contributing to increased active site exposure and improved OER kinetics. Density functional theory simulations demonstrate that Zn incorporation synergistically optimizes the kinetic energy barrier by promoting co‐adsorption of OER intermediates on a Co site and its adjacent Zn site. As a result, the modified CoSe2 NAs electrode shows optimized catalytic activity and excellent stability with the low overpotential of only 286 mV required to drive a current density of 10 mA cm−2 in an alkaline electrolyte.

Synergistic Engineering of Se Vacancies and Heterointerfaces in Zinc‐Cobalt Selenide Anode for Highly Efficient Na‐Ion Batteries

“…The high-resolution Se 3d spectrum (Figure 3f) discloses three deconvoluted peaks at 53.6 eV (assigned to Se 3d 5/2 ), 54.6 and 55.6 eV (related to Se 3d 3/2 ), corresponding to Co-Se and Zn-Se bonds. [35,36] Notably, the characteristic peaks of Zn 2p shift toward higher binding energy direction and Se 3d shift to lower binding energy direction compared with those of ZnSe/CN (Figures S13 and S14, Supporting Information), suggesting an increased electron cloud density around the heterostructure and further demonstrating the successful construction of heterojunction between ZnSe and CoSe 2 . [40,41] Besides, the other peak at 59.3 eV discloses the presence of SeO x in the typical sample, which was caused by the slight surface oxidation during testing.…”

“…The lattice distortion and discontinuous lattice fringes marked by red frameworks in Figure 2h-k confirm the existence of lattice mismatch, demonstrating the strong electronic interaction between ZnSe and CoSe 2 with Se vacancies, which maybe produce more accessible active sites for Na + -storage, accelerate ion diffusion kinetic and improve the structural stability benefiting for the resulted electrochemical performance. [33][34][35][36] Electron paramagnetic resonance (EPR) spectrum shown in Figure 2l displays a significant EPR signal at g = 2.003, which was caused by the trapped electrons from Se vacancies, confirming the presence of Se vacancies in the sample. [34] The coexistence of ZnSe and CoSe 2 in the typical sample was further confirmed by selected area electron diffraction patterns (Figure S8, Supporting Information), revealing the polycrystalline nature of the typical sample.…”

Tuning the intrinsic catalytic activities of oxygen-evolution catalysts by doping: a comprehensive review

“…Open Fe-doped NiSe2 171 231 mV @ 10 mA cm -2 83 20 h @ mA cm -2 1 M KOH Fe-doped Ni3Se4 172 225 mV @ 10 mA cm -2 41 26 h @ 10 mA cm -2 1 M KOH Fe-doped Ni3Se2 173 225 mV @ 10 mA cm -2 35.3 12 h @ 20 mA cm -2 1 M KOH Ni1.12Fe0.49Se2 174 227 mV @ 10 mA cm -2 37.9 10 h @ 10 mA cm -2 1 M KOH Ni0.04Fe0.16 Co0.8Se2 175 230 mV @ 10 mA cm -2 39 15 h @ 1.5 V vs RHE 1 M KOH VSe-Ni0.70Fe0.30Se2 176 210 mV @ 10 mA cm -2 61 20 h @ 10 mA cm -2 1 M KOH Zn-doped CoSe2 177 286 mV @ 10 mA cm -2 37 24 h @ 10, 20, 50 mA cm -2 1 M KOH In addition to the Fe inclusion, doping of other metals such as Ni, 152,178 Co, 148 Mn, 150 Zn, 160 Ce, 147 and Al 146 are also found to be enhancing the OER activity of metal sulfides. For instance, Lin et al fabricated…”

Advanced Transition Metal‐Based OER Electrocatalysts: Current Status, Opportunities, and Challenges

“…Doping engineering is applied to boost the OER activity of CoSe 2 . By incorporating Zn into CoSe 2 , the DOS of Co decreases, leading to a weak binding strength of intermediates on Co. [207] Besides, the elongated or compressed CoSe 6 octahedra due to Jahn-Teller effect are generated in the lattice, which modulate d-orbital distribution and adsorption properties of CoSe 2 . Atomically coordinated PtCoSe moieties in defective CoSe 2 are synthesized through filling the plasma-created Se vacancies in CoSe 2 with single Pt atomic species.…”