The development of low-cost, efficient, and high atomic economy electrocatalysts for hydrogen evolution reaction(HER) in the entire p H range for sustainable hydrogen production is of great importance but still challe...The development of low-cost, efficient, and high atomic economy electrocatalysts for hydrogen evolution reaction(HER) in the entire p H range for sustainable hydrogen production is of great importance but still challenging. Herein, we synthesize a highly dispersed N-doped carbon frames(NCFs) anchored with Co single atoms(SAs) and Co nanoparticles(NPs) catalyst by a doping-adsorption-pyrolysis strategy for electrocatalytic hydrogen evolution. The Co SAs-Co NPs/NCFs catalyst exhibits an excellent HER activity with small overpotential, low Tafel slope, high turnover frequency as well as remarkable stability. It also exhibits a superior HER performance in the entire p H range. Combining with experimental and theoretical calculation, we find that Co SAs with Co-N_(3) coordination structure and Co NPs have a strong interaction for promoting synergistic HER electrocatalytic process. The H_(2)O molecule is easily activated and dissociated on Co NPs, while the generated H^(*) is easily adsorbed on Co SAs for HER, which makes the Co SAs-Co NPs/NCFs catalyst exhibit more suitable H adsorption strength and more conducive to the activation and dissociation of H_(2)O molecules. This work not only proposes a novel idea for constructing coupling catalyst with atomic-level precision, but also provides strong reference for the development of high-efficiency HER electrocatalysts for practical application.展开更多
Large scale synthesis of high-efficiency bifunctional electrocatalyst based on cost-effective and earth-abundant transition metal for overall water splitting in the alkaline environment is indispensable for renewable ...Large scale synthesis of high-efficiency bifunctional electrocatalyst based on cost-effective and earth-abundant transition metal for overall water splitting in the alkaline environment is indispensable for renewable energy conversion.In this regard,meticulous design of active sites and probing their catalytic mechanism on both cathode and anode with different reaction environment at molecular-scale are vitally necessary.Herein,a coordination environment inheriting strategy is presented for designing low-coordination Ni^(2+)octahedra(L-Ni-8)atomic interface at a high concentration(4.6 at.%).Advanced spectroscopic techniques and theoretical calculations reveal that the self-matching electron delocalization and localization state at L-Ni-8 atomic interface enable an ideal reaction environment at both cathode and anode.To improve the efficiency of using the self-modification reaction environment at L-Ni-8,all of the structural features,including high atom economy,mass transfer,and electron transfer,are integrated together from atomic-scale to macro-scale.At high current density of 500 mA/cm2,the samples synthesized at gram-scale can deliver low hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)overpotentials of 262 and 348 mV,respectively.展开更多
The incorporation of small guest molecules or ions by bottom-up hydrothermal synthesis has recently emerged as a promising new way to engineer 1T-phase MoS2 with high hydrogen evolution reaction (HER) activity. Howe...The incorporation of small guest molecules or ions by bottom-up hydrothermal synthesis has recently emerged as a promising new way to engineer 1T-phase MoS2 with high hydrogen evolution reaction (HER) activity. However, the mechanism of the associated structural evolution remains elusive and controversial, leading to a lack of effective routes to prepare 1T-phase MoS2 with controlled structure and morphology, along with high purity and stability. Herein, urea is chosen as precursor of small molecules or ions to simultaneously engineer the phase (16.4%, - 69.4%, and -90.2% of 1T phase) and size (98.8, - 151.6, and - 251.8 nm for the 90.2% 1T phase) of MoS2 nanosheets, which represent an ideal model system for investigating the structural evolution in these materials, as well as developing a new type of 1T-phase MoS2 arrays. Using reaction intermediate monitoring and theoretical calculations, we show that the oriented growth of 1T-phase MoS2 is controlled by ammonia-assisted assembly recrystallization, and stabilization processes. A superior HER performance in acidic media is obtained, with an overpotential of only 76 mV required to achieve a stable current density of 10 mA.cm-2 for 15 h. This excellent performance is attributed to the unique array structure, involving well-dispersed, edge-terminated, and high-purity 1T-phase MoS2 nanosheets.展开更多
基金supported by the Taishan Scholars Program of Shandong Province(tsqn201909065)the Shandong Provincial Natural Science Foundation(ZR2020QB174)+3 种基金the Petro China Innovation Foundation(2019D-5007-0401)the National Natural Science Foundation of China(21776315,22108306)the Fundamental Research Funds for the Central Universities(19CX02008A,19CX05001A)the Postgraduate Innovation Fund of China University of Petroleum(East China)(YCX2020037)。
文摘The development of low-cost, efficient, and high atomic economy electrocatalysts for hydrogen evolution reaction(HER) in the entire p H range for sustainable hydrogen production is of great importance but still challenging. Herein, we synthesize a highly dispersed N-doped carbon frames(NCFs) anchored with Co single atoms(SAs) and Co nanoparticles(NPs) catalyst by a doping-adsorption-pyrolysis strategy for electrocatalytic hydrogen evolution. The Co SAs-Co NPs/NCFs catalyst exhibits an excellent HER activity with small overpotential, low Tafel slope, high turnover frequency as well as remarkable stability. It also exhibits a superior HER performance in the entire p H range. Combining with experimental and theoretical calculation, we find that Co SAs with Co-N_(3) coordination structure and Co NPs have a strong interaction for promoting synergistic HER electrocatalytic process. The H_(2)O molecule is easily activated and dissociated on Co NPs, while the generated H^(*) is easily adsorbed on Co SAs for HER, which makes the Co SAs-Co NPs/NCFs catalyst exhibit more suitable H adsorption strength and more conducive to the activation and dissociation of H_(2)O molecules. This work not only proposes a novel idea for constructing coupling catalyst with atomic-level precision, but also provides strong reference for the development of high-efficiency HER electrocatalysts for practical application.
基金supported by the National Natural Science Foundation of China(22108306 and 22078362)Shandong Provincial Natural Science Foundation(ZR2021YQ15 and ZR2020QB174)+3 种基金PetroChina Innovation Foundation(2019D-5007-0401)Taishan Scholars Program of Shandong Province(tsqn201909065)the Fundamental Research Funds for the Central Universities(22CX07009A,19CX05001A)Postgraduate Innovation Fund of China University of Petroleum(East China)(YCX2020037).
基金supported by the National Natural Science Foundation of China(No.21676300)the Shandong Provincial Natural Science Foundation(No.ZR2018MB035)+3 种基金the Fundamental Research Funds for the Central Universities(Nos.19CX02008A and 16CX06007A)PetroChina Innovation Foundation(No.2019D-5007-0401)Taishan Scholars Program of Shandong Province(No.tsqn201909065)Tsinghua University Initiative Scientific Research Program.
文摘Large scale synthesis of high-efficiency bifunctional electrocatalyst based on cost-effective and earth-abundant transition metal for overall water splitting in the alkaline environment is indispensable for renewable energy conversion.In this regard,meticulous design of active sites and probing their catalytic mechanism on both cathode and anode with different reaction environment at molecular-scale are vitally necessary.Herein,a coordination environment inheriting strategy is presented for designing low-coordination Ni^(2+)octahedra(L-Ni-8)atomic interface at a high concentration(4.6 at.%).Advanced spectroscopic techniques and theoretical calculations reveal that the self-matching electron delocalization and localization state at L-Ni-8 atomic interface enable an ideal reaction environment at both cathode and anode.To improve the efficiency of using the self-modification reaction environment at L-Ni-8,all of the structural features,including high atom economy,mass transfer,and electron transfer,are integrated together from atomic-scale to macro-scale.At high current density of 500 mA/cm2,the samples synthesized at gram-scale can deliver low hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)overpotentials of 262 and 348 mV,respectively.
基金supported by the Research Grants Council of Hong Kong (T23-407/13-N)Innovation and Technology Commission (ITS/088/17)+5 种基金Start-up funds from Central Organization Department and South China University of Technologyfund from the Guangdong Science and Technology Program (2020B121201003)the National Natural Science Foundation of China (21776315)Petro China Innovation Foundation (2017D5007-0402)the Pearl River Talent Program (2019ZT08L075, 2019QN01L118)Fundamental Research Funds for the Central Universities (19CX05001A)。
文摘The incorporation of small guest molecules or ions by bottom-up hydrothermal synthesis has recently emerged as a promising new way to engineer 1T-phase MoS2 with high hydrogen evolution reaction (HER) activity. However, the mechanism of the associated structural evolution remains elusive and controversial, leading to a lack of effective routes to prepare 1T-phase MoS2 with controlled structure and morphology, along with high purity and stability. Herein, urea is chosen as precursor of small molecules or ions to simultaneously engineer the phase (16.4%, - 69.4%, and -90.2% of 1T phase) and size (98.8, - 151.6, and - 251.8 nm for the 90.2% 1T phase) of MoS2 nanosheets, which represent an ideal model system for investigating the structural evolution in these materials, as well as developing a new type of 1T-phase MoS2 arrays. Using reaction intermediate monitoring and theoretical calculations, we show that the oriented growth of 1T-phase MoS2 is controlled by ammonia-assisted assembly recrystallization, and stabilization processes. A superior HER performance in acidic media is obtained, with an overpotential of only 76 mV required to achieve a stable current density of 10 mA.cm-2 for 15 h. This excellent performance is attributed to the unique array structure, involving well-dispersed, edge-terminated, and high-purity 1T-phase MoS2 nanosheets.