Green synthesis of Ni3S2 nanoparticles from a nontoxic sulfur source for urea electrolysis with high catalytic activity

CoFe-Layered Double Hydroxide Needles on MoS2/Ni3S2 Nanoarrays for Applications as Catalysts for Hydrogen Evolution and Oxidation of Organic Chemicals

“…Similarly, a nitrogen-vacancy-rich Co 2 N/CoP@CC p–n junction with excellent OWS performance was reported by Wang’s group, confirming that the built-in electric field formed by the p–n interface and nitrogen vacancies jointly enhanced HER and OER . Some studies have shown that Ni 3+ can be regarded as the active center to promote the oxidation of the urea molecule . Nickel-rich Ni 3 S 2 with abundant Ni–S and Ni–Ni bonds drive the formation of UOR intermediates (OOH*). , Layered double hydroxides (LDHs) are capable of producing surface hydroxides as active substances to optimize the H 2 O dissociation process. − As a member of the LDH family, CoFe LDH is often used to improve the OER performance of catalysts. − Furthermore, many studies have reported that one-dimensional (1D) nanostructures enhanced electrocatalytic performances attributed to their increased specific surface area and active exposed sites, which facilitate ion transport, diminish the diffusion paths of electrolytes, and consequently reduce the cost of electrocatalysts. − …”

“…42 Some studies have shown that Ni 3+ can be regarded as the active center to promote the oxidation of the urea molecule. 43 Nickel-rich Ni 3 S 2 with abundant Ni−S and Ni−Ni bonds drive the formation of UOR intermediates (OOH*). 44,45 Layered double hydroxides (LDHs) are capable of producing surface hydroxides as active substances to optimize the H 2 O dissociation process.…”

Co2P–Ni3S2 Heterostructured Nanocrystals as Catalysts for Urea Electrooxidation and Urea-Assisted Water Splitting

“…The fine scanning spectrum of Ni 2p is shown in Figure 3c, consisting of four pairs of peaks belonging to Ni 0 (853.6 eV, 871.2 eV), Ni 2+ (855.3 eV, 872.9 eV), Ni 3+ (856.6 eV, 874.2 eV) and satellite peaks (861.5 eV, 880.0 eV). 48,49 The occurrence of Ni(0) is caused by the H 2 /Ar reduction. Compared with Ni 3 S 2 /C, there are more Ni 3+ components in Co 2 P−Ni 3 S 2 -2, which proves that the surface of Co 2 P−Ni 3 S 2 -2 may be more prone to forming NiOOH sites.…”

“…The P–O bond is due to the unavoidable exposure of the sample to the air, resulting in the surface of the phosphide will be oxidized by the air, and the existence of P–C bonds proves that some phosphorus species were incorporated into the C support after phosphating. − The difference in P components indicates that most of the P species in CoP/C have been lost during subsequent vulcanization and high-temperature calcination processes. The fine scanning spectrum of Ni 2p is shown in Figure c, consisting of four pairs of peaks belonging to Ni 0 (853.6 eV, 871.2 eV), Ni 2+ (855.3 eV, 872.9 eV), Ni 3+ (856.6 eV, 874.2 eV) and satellite peaks (861.5 eV, 880.0 eV). , The occurrence of Ni(0) is caused by the H 2 /Ar reduction. Compared with Ni 3 S 2 /C, there are more Ni 3+ components in Co 2 P–Ni 3 S 2 -2, which proves that the surface of Co 2 P–Ni 3 S 2 -2 may be more prone to forming NiOOH sites.…”

Recent Development of Nickel-Based Electrocatalysts for Urea Electrolysis in Alkaline Solution

“…Here, future perspectives are discussed: Developing highly efficient UOR catalysts, in terms of boosted catalytic current, low overpotential and durable catalytic performance, is highly desirable. The majority of the prepared catalysts are nickel oxides and hydroxides at early stages, while nickel sulfides [ 115 , 116 , 117 , 118 ], selenides [ 62 , 63 ], phosphides [ 119 , 120 ] and nitrides [ 111 ] have shown appreciable UOR performance in recent years. In addition, Ni-based Prussian blue analogues [ 17 ] and perovskites [ 121 ] have also been revealed as promising candidates for the UOR.…”