Synergistic effect customized for cobalt pentlandite (Co,Ni,Fe)9S8 accelerated charge transfer toward highly efficient oxygen evolution reaction

Internal and External Cultivation Strategy toward Efficient Electrochemical Oxygen Evolution in Cobalt Pentlandite

“…The stability of the V-CNFS/Ni 9 S 8 electrocatalyst for the OER was evaluated by the chronoamperometric method (CP). As shown in Figure 4(f), under a constant current density of 50 mA cm −2 , the overpotential only lost 10.8 mV after CP testing for 72 h, which is better than the stability of CNFS (overpotential only loss of 27 mV after CP testing for 60 h), 9 demonstrating the heterojunction structure of V-CNFS/ Ni 9 S 8 increases the stability of the catalyst. 41 The stability of the catalyst was further confirmed by characterizing the recovered catalyst using SEM, Raman, and XPS techniques.…”

“…Compared with the results before testing, a band centered at around 1058 cm −1 was observed in the Raman spectrum of the sample after CP testing, as shown in Figure 5(a), corresponding to metal (oxygen) hydroxides, indicating structural reconstruction during the OER process, which is more favorable for OER. 9,42,43 Regarding the XPS test results of V-CNFS/Ni 9 S 8 after CP testing shown in Figure 5(b−f), significant changes were observed in the S 2p spectra. Two new peaks appeared at 169.4 and 170.3 eV, corresponding to the binding energy of sulfonic acid in the Nafion binder.…”

“…The formation of heterogeneous interfaces can cause the redistribution of electrons at the interface and enhance the activity of active sites. 9,30,31 The XPS spectrum of V 2p is shown in Figure 3(e), and the binding energy of V 2p 3/2 is 515.70 eV, indicating the trivalent state of V. The signals of S 2p 1/2 and S 2p 3/2 (Figure 3(f)) were negatively shifted to 160.3 and 161.3 eV, respectively, in V-CNFS/Ni 9 S 8 . 32 The slight shift could be attributed to the regulation of the electronic structure of CNFS by the introduction of vanadium atoms, facilitating electron transfer within the catalyst.…”

“…Common sulfide ores include pyrite, sphalerite, chalcopyrite, etc., accounting for about 1.5% of the sulfur content in the crust of Earth. , Among them, cobalt pentlandite (Co, Ni, Fe) 9 S 8 (CNFS) exhibits good catalytic activity in the oxygen evolution reaction (OER) due to its unique crystal structure, synergistic effect among the three metals, and excellent electron transfer performance. However, the pristine catalytic active sites of cobalt pentlandite need to be further increased, and their interaction with OER reaction intermediates (*OH → *O) is relatively strong, which affects their catalytic activity . Therefore, there is an urgent need for more optimization strategies to improve the OER performance of cobalt pentlandite.…”

“…However, the pristine catalytic active sites of cobalt pentlandite need to be further increased, and their interaction with OER reaction intermediates (*OH → *O) is relatively strong, which affects their catalytic activity. 9 Therefore, there is an urgent need for more optimization strategies to improve the OER performance of cobalt pentlandite.…”