The research of superior water oxidation electrodes is essential for the green energy in the form of hydrogen by way of electrolytic water splitting, and still remains challenging. Based upon dealloying foam, Fe-Ni hy...The research of superior water oxidation electrodes is essential for the green energy in the form of hydrogen by way of electrolytic water splitting, and still remains challenging. Based upon dealloying foam, Fe-Ni hydroxide nanosheets network structure is designed on the surface of Fe-Ni alloy foam. The ratio of Ni/Fe elements was adjusted to realize the optimal catalytic activities for oxygen evolution reaction（OER） and hydrogen evolution reaction（HER）. The obtained electrode of Fe-Ni hydroxide nanosheets/Fe-Ni alloy foam-60% Fe（FN LDH/FNF-60, 60 is the percentage of Fe content） possess low overpotential of 261 mV to reach 10 mA/cm;, small Tafel slope（85.5 mV/dec）, and superior long-term stability（remaining 10 mA/cm;for over 14 h without attenuation） toward OER in 1.0 mol/L KOH.Moreover, an alkaline water electrolyzer is constructed with the FN LDH/FNF-60 as anode and Ni（OH）;/Fe-Ni alloy foam-25% Fe(Ni（OH）;/FNF-25) as cathode, which displays superior electrolytic performance（affording 10 mA/cm;at 1.62 V） and lasting durability.展开更多
Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aim...Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co_(2)P HMs).The obtained Ru NCs/Co_(2)P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4) and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co_(2)P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4),which is below that of the commercial RuO_(2) electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm^(2) at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V).展开更多
Ultra-broadband supercontinuum(SC)lasers covering the mid-infrared(MIR)region have significant applications in trace substance detection,national defense,and biomedical fields.Currently,high-power SC spanning2–5μm i...Ultra-broadband supercontinuum(SC)lasers covering the mid-infrared(MIR)region have significant applications in trace substance detection,national defense,and biomedical fields.Currently,high-power SC spanning2–5μm is still dominated by traditional fluoride(InF_(3))fibers.Although tellurite fibers,with their excellent chemical and thermal stability,have demonstrated significantly higher power scalability compared to other MIR fibers,their spectral broadening capabilities in the 4–5μm region remain largely unexplored.Here,we demonstrate a>10 W ultra-broadband flat SC spanning the 1.8–5.1μm spectral range in a fluorotellurite fiber using a cascaded soliton self-frequency shifting technique.The fluorotellurite fiber is precisely tapered to reconstruct dispersion and nonlinearity,which facilitates the evolution of the pre-stage Raman soliton into higherorder solitons,thereby enabling a new round of“rapid relay fission.”At a low pump power of 7.5 W,we also achieved a high-power(0.5 W)Raman soliton(60 fs)at 4.3μm.These results,for the first time,to our knowledge,demonstrate that tapered fluorotellurite fibers can be used for high-power femtosecond pulse generation beyond4μm and high-power SC generation beyond 5μm,establishing them as an exceptional nonlinear medium for the development of high-power MIR fiber lasers in the 4–5μm spectral region.展开更多
In this work,we demonstrate the generation of high-performance tunable Raman solitons beyond 3μm in a 10 cm,large-core(40μm)fluorotellurite fiber.The pump source is a high-peak-power Raman soliton generated through ...In this work,we demonstrate the generation of high-performance tunable Raman solitons beyond 3μm in a 10 cm,large-core(40μm)fluorotellurite fiber.The pump source is a high-peak-power Raman soliton generated through soliton fission in a silica fiber.By further cascading the 10 cm highly nonlinear fluorotellurite fiber,this Raman soliton undergoes successive high-order soliton fission and soliton self-frequency shift with a tunable range of 2.7–3.3μm.Such an ultra-short-length and ultra-large-core fiber significantly reduces the pulse width of the 3.3μm Raman soliton to 55 fs,doubling the peak power to 2.3 MW compared to previous studies.Furthermore,owing to the seed's high-repetition-frequency feature,the 3.3μm Raman soliton's power exceeds 2 W.These performance metrics represent the highest levels achieved for Raman solitons at wavelengths above 3μm,offering a simple and effective new approach for generating high-peak-power femtosecond pulses in the mid-infrared spectral region.展开更多
Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly....Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly. It introduces the progresses on molecular self-assembly of alkanethiols in detail.展开更多
基金supported by the Science and Technology Planning Project of Guangdong Province,China(No.2017B090916002)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(No.2016TQ03N541)+2 种基金Guangdong Natural Science Funds for Distinguished Young Scholar(No.2017B030306001)the National Natural Science Foundation of China(No.91745203)Guangdong Innovative and Entrepreneurial Research Team Program(No.2014ZT05N200)
文摘The research of superior water oxidation electrodes is essential for the green energy in the form of hydrogen by way of electrolytic water splitting, and still remains challenging. Based upon dealloying foam, Fe-Ni hydroxide nanosheets network structure is designed on the surface of Fe-Ni alloy foam. The ratio of Ni/Fe elements was adjusted to realize the optimal catalytic activities for oxygen evolution reaction（OER） and hydrogen evolution reaction（HER）. The obtained electrode of Fe-Ni hydroxide nanosheets/Fe-Ni alloy foam-60% Fe（FN LDH/FNF-60, 60 is the percentage of Fe content） possess low overpotential of 261 mV to reach 10 mA/cm;, small Tafel slope（85.5 mV/dec）, and superior long-term stability（remaining 10 mA/cm;for over 14 h without attenuation） toward OER in 1.0 mol/L KOH.Moreover, an alkaline water electrolyzer is constructed with the FN LDH/FNF-60 as anode and Ni（OH）;/Fe-Ni alloy foam-25% Fe(Ni（OH）;/FNF-25) as cathode, which displays superior electrolytic performance（affording 10 mA/cm;at 1.62 V） and lasting durability.
基金supported by Fundamental Research Funds for Central Universities of SCUT(No.D2182400)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(No.2016TQ03N541)+1 种基金Guangdong Natural Science Funds for Distinguished Young Scholar(No.2017B030306001)the National Natural Science Foundation of China(No.51972147)。
文摘Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co_(2)P HMs).The obtained Ru NCs/Co_(2)P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4) and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co_(2)P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4),which is below that of the commercial RuO_(2) electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm^(2) at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V).
基金National Natural Science Foundation of China(62005004,61675009)Natural Science Foundation of Beijing Municipality(4204091,KZ201910005006)China Postdoctoral Science Foundation(212423)。
文摘Ultra-broadband supercontinuum(SC)lasers covering the mid-infrared(MIR)region have significant applications in trace substance detection,national defense,and biomedical fields.Currently,high-power SC spanning2–5μm is still dominated by traditional fluoride(InF_(3))fibers.Although tellurite fibers,with their excellent chemical and thermal stability,have demonstrated significantly higher power scalability compared to other MIR fibers,their spectral broadening capabilities in the 4–5μm region remain largely unexplored.Here,we demonstrate a>10 W ultra-broadband flat SC spanning the 1.8–5.1μm spectral range in a fluorotellurite fiber using a cascaded soliton self-frequency shifting technique.The fluorotellurite fiber is precisely tapered to reconstruct dispersion and nonlinearity,which facilitates the evolution of the pre-stage Raman soliton into higherorder solitons,thereby enabling a new round of“rapid relay fission.”At a low pump power of 7.5 W,we also achieved a high-power(0.5 W)Raman soliton(60 fs)at 4.3μm.These results,for the first time,to our knowledge,demonstrate that tapered fluorotellurite fibers can be used for high-power femtosecond pulse generation beyond4μm and high-power SC generation beyond 5μm,establishing them as an exceptional nonlinear medium for the development of high-power MIR fiber lasers in the 4–5μm spectral region.
基金supported by the National Natural Science Foundation of China(Grant Nos.62005004 and 61675009)the Natural Science Foundation of Beijing Municipality(Grant Nos.4204091 and KZ201910005006)the China Postdoctoral Science Foundation(Grant No.212423)。
文摘In this work,we demonstrate the generation of high-performance tunable Raman solitons beyond 3μm in a 10 cm,large-core(40μm)fluorotellurite fiber.The pump source is a high-peak-power Raman soliton generated through soliton fission in a silica fiber.By further cascading the 10 cm highly nonlinear fluorotellurite fiber,this Raman soliton undergoes successive high-order soliton fission and soliton self-frequency shift with a tunable range of 2.7–3.3μm.Such an ultra-short-length and ultra-large-core fiber significantly reduces the pulse width of the 3.3μm Raman soliton to 55 fs,doubling the peak power to 2.3 MW compared to previous studies.Furthermore,owing to the seed's high-repetition-frequency feature,the 3.3μm Raman soliton's power exceeds 2 W.These performance metrics represent the highest levels achieved for Raman solitons at wavelengths above 3μm,offering a simple and effective new approach for generating high-peak-power femtosecond pulses in the mid-infrared spectral region.
文摘Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers the suggestion, principle and the newest progresses on self-assembly. It introduces the progresses on molecular self-assembly of alkanethiols in detail.
