Showing papers by "Yunchen Du published in 2023"
TL;DR: In this article , a dual-pathway optimization strategy was proposed to consolidate the electromagnetic functions of core-shell Fe3O4@C microcapsules for the first time, and the optimal composite will present good microwave absorption performance, whose effective absorption bandwidth (EAB) and minimum RL value are 5.4 GHz and −36.1 dB (5.9 GHz, 4.0 mm), respectively.
9 citations
6 citations
TL;DR: In this paper , a novel strong phosphide-metaphosphate interaction (SPmPI) was discovered in the RuP/CoNiP4O12 catalyst for the first time.
Abstract: Strong metal-support interaction (SMSI) is a crucial concept in heterogeneous catalysis, which has been utilized to design efficient catalysts for electrocatalytic overall water splitting. Herein, a novel strong phosphide-metaphosphate interaction (SPmPI) is discovered in the RuP/CoNiP4O12 catalyst for the first time. The SPmPI leads to efficient electron transfer from RuP to CoNiP4O12 support, endowing the catalyst with a unique coordination environment of Ru-P and Ru-O, which is demonstrated to greatly facilitate the rate-determining water dissociation step. As a result, the RuP/CoNiP4O12 catalyst with proper Ru-P and Ru-O coordination numbers requires an ultralow overpotential of 27 mV to deliver a current density of 10 mA cm-2 for hydrogen evolution reaction (HER) in alkaline media. Moreover, the catalyst inherits the remarkable catalytic activity from the CoNiP4O12 support for oxygen evolution reaction (OER), and therefore is also effective for overall water splitting (requiring 1.56 V to achieve 10 mA cm-2 current density). This work not only reports a highly efficient catalyst for electrocatalytic overall water splitting, but also provides a novel concept of SPmPI for designing supported catalyst in heterogeneous catalysis.
4 citations
TL;DR: In this article , a bifunctional molybdenum-doped nickel sulfide on nickel foam (Mo-NiSx/NF) was proposed for magnetic field-enhanced overall water splitting under alkaline conditions.
Abstract: Herein, we report bifunctional molybdenum-doped nickel sulfide on nickel foam (Mo-NiSx/NF) for magnetic field-enhanced overall water splitting under alkaline conditions. Proper doping of Mo can lead to optimization of the electronic structure of NiSx, which accelerates the dissociation of H2O and the adsorption of OH− in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) processes, respectively. In addition, the magnetically active Mo-NiSx/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic (FM) exchange-field penetration effect. As a result, Mo-NiSx/NF requires low overpotentials of 307 mV at 50 mA cm−2 (for OER) and 136 mV at 10 mA cm−2 (for HER) under a magnetic field of 10000 G. Furthermore, the electrolytic cell constructed by the bifunctional Mo-NiSx/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm−2 with optimal stability over 60 h under the magnetic field. Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.
2 citations
TL;DR: In this paper , the surface oxidation of transition metal sulfides (TMSs) is considered for hydrogen evolution reaction (HER) and an effective strategy for reducing surface oxidation degree of easily oxidized CoS2 is demonstrated.
Abstract: Transition metal sulfides (TMSs) are promising electrocatalysts for hydrogen evolution reaction (HER), while TMSs usually suffer from inevitable surface oxidation in air, and the impact of the surface oxidation on their HER catalytic activity remains unclear. Herein, we demonstrate an effective strategy for reducing the surface oxidation degree of easily oxidized CoS2 by introducing glued vanadium pentoxide (V2O5) nanoclusters, taking advantage of the preferential adsorption and strong interaction between high-valence V and O2. Combining oxidation protection and elaborate oxidation control experiments reveal that reduced surface oxidation degree of CoS2 is conducive to affording promising HER catalytic performance, as the oxidized surface of CoS2 can hinder the dissociation of water and thus is harmful to the HER process. Direct evidence is provided that surface oxidation should be carefully considered for TMS-based HER catalysts. The present work not only develops a new strategy for protecting CoS2 from surface oxidation, but also provides deep insight into the impact of surface oxidation on the HER performance of transition metal compounds.
1 citations
TL;DR: In this article , a series of basic cobalt salts with distinct acidic anion Co(OH)x(A)y are synthesized via a hydrothermal strategy, and the order of the OER activity is determined to be Co(HO)(CO3)0.5 > Co2(OH)-3Cl > Co( OH)F > CoOH)2.
Abstract: Basic cobalt salts with distinct acidic anion Co(OH)x(A)y are efficient electrocatalysts toward the oxygen evolution reaction (OER). However, plenty of present studies are still in the try-and-wrong stage, while the underlying anion effect remains unclear. Herein, a series of Co(OH)x(A)y (A = F–, Cl–, and CO32–) are synthesized via a hydrothermal strategy, and the order of the OER activity is determined to be Co(OH)(CO3)0.5 > Co2(OH)3Cl > Co(OH)F > Co(OH)2. X-ray photoelectron spectroscopy and soft X-ray absorption spectroscopy studies reveal that these Co(OH)x(A)y materials undergo surface oxidation during the OER process, and the highly active Co(IV) content is the dominant factor in deciding the OER performance. Furthermore, quantitative analysis of anion concentrations in the electrolyte solution reveals that the anion leaching ability in Co(OH)x(A)y directly relates to the Co(IV) content and finally the OER catalytic activity, which is the essence of the anion effect and can be summarized as an “anion leaching─metal oxidation” model. Our work not only provides deep understanding of the anion effect of metal basic salt-based OER catalysts but also profound insights for the activation process of the OER pre-catalysts.
01 Jan 2023
TL;DR: In this paper , a topological deformation of bulky Ni-MOF particles is induced to generate Ni-MoF aerogel assembled by crosslinked fibers, and then converted to Ni/C composite aerogels (NCCAs) through controllable high-temperature pyrolysis.
TL;DR: Porous nitrogen-doped carbon nanocages (PNCCs) are fabricated by one-step pyrolysis of energetic Zn-based MOF (MET-6) and employed as highly efficient PMS activator to decompose organic micropollutants as discussed by the authors .