Developing large-scale electrocatalysts using molecular complexes for the oxygen evolution reaction(OER)is of great importance. Herein, four cobalt porphyrins and corroles are deposited on electrode substrates using a...Developing large-scale electrocatalysts using molecular complexes for the oxygen evolution reaction(OER)is of great importance. Herein, four cobalt porphyrins and corroles are deposited on electrode substrates using a simple and fast electropolymerization method. Our results showed that Co-1-P@CC, formed by electropolymerizing Co tetrakis(p-N-pyrrolylphenyl)porphyrin(Co-1-P) on carbon cloth(CC), is the most active OER catalyst in the examined Co porphyrins and corroles in alkaline aqueous solutions by displaying an onset overpotential of 380 m V. Long-term electrolysis tests confirmed the stability of these electropolymerized films by functioning as OER electrocatalysts.展开更多
Gas sensors have a wide variety of applications.Among various existing gas sensing technologies,optical gas sensors have outstanding advantages.The development of the Internet of Things and consumer electronics has pu...Gas sensors have a wide variety of applications.Among various existing gas sensing technologies,optical gas sensors have outstanding advantages.The development of the Internet of Things and consumer electronics has put stringent requirements on miniaturized gas sensing technology.Here,we demonstrate a chip-scale silicon substrate-integrated hollow waveguide(Si-iHWG) to serve as an optical channel and gas cell in an optical gas sensor.It is fabricated through silicon wafer etching and wafer bonding.The Si-i HWG chip is further assembled with an off-chip light source and detector to build a fully functional compact nondispersive infrared(NDIR) CO_(2) sensor.The chip size is 10 mm × 9 mm,and the dimension of the sensor excluding the microcontroller board is 50 mm × 25 mm × 16 mm.This chip solution with compactness,versatility,robustness,and low cost provides a cost-effective platform for miniaturized optical sensing applications ranging from air quality monitoring to con-sumer electronics.展开更多
Microstructure and mechanical properties of an extruded Mg-2Dy-0.5Zn （at.%） alloy during isothermal ageing at 180℃ were investigated. Microstructure of the as-extruded alloy is mainly composed of α-Mg phase, 14H l...Microstructure and mechanical properties of an extruded Mg-2Dy-0.5Zn （at.%） alloy during isothermal ageing at 180℃ were investigated. Microstructure of the as-extruded alloy is mainly composed of α-Mg phase, 14H long period stacking order （LPSO） phase and small amounts of （Mg, Zn）=Dy particle phases. During ageing, the 14H LPSO phase forms and develops and its volume fraction increases with increasing ageing time. Tensile test showed that the peak-aged alloy exhibits similar yield and ultimate tensile strengths and elongation to failure at room temperature, 100℃ and 200℃, but excellent elevated temperature strengths at 300℃ as compared to the as-extruded and over-aged alloys. The analysis showed that the excellent elevated temperature strengths of the peak-aged alloy are attributed to the LPSO phase strengthening and the grain refinement strengthening, and the role of the LPSO strengthening is related to not only its amount, but also its morphology.展开更多
Developing highly efficient electrocatalysts for the CO_(2) reduction reaction(CO_(2)RR)has attracted increasing interest in the past decade.Herein,we report on the design and synthesis of Fe porphyrin 1 with an appen...Developing highly efficient electrocatalysts for the CO_(2) reduction reaction(CO_(2)RR)has attracted increasing interest in the past decade.Herein,we report on the design and synthesis of Fe porphyrin 1 with an appended N,N-di(2-picolyl)ethylenediamine(DPEN)unit that boosts electrocatalytic activity for CO_(2)-to-CO conversion in acetonitrile with water as the proton source.By mimicking carbon monoxide dehydrogenase(CODH),1 has poly-pyridine/amine units located at the active site to form hydrogen-bonded water-containing networks that enable fast proton transfer.The protonated and positively charged DPEN unit can also stabilize CO_(2) reduction intermediates through electrostatic and hydrogen-bonding interactions.These factors make 1 a highly active electrocatalyst for the CO_(2)RR by achieving a TOFmax of 5.0×10^(4)s^(−1) with water providing the protons.These critical roles of the DPEN unit in the CO_(2)RR are further supported by theoretical studies.This work is significant to highlight the benefits of using molecular catalysts to elucidate structural effects.展开更多
基金support from National Natural Science Foundation of China (Nos. 21773146 and 21902099)China Postdoctoral Science Foundation (No. 2018M631120)+2 种基金Shaanxi Province Postdoctoral Science Foundation (No. 2018BSHEDZZ107)Fundamental Research Funds for the Central Universities (Nos. GK202103045 and GK202103050)Research funds of Shaanxi Normal University, and the open fund of State Key Laboratory of Structural Chemistry。
文摘Developing large-scale electrocatalysts using molecular complexes for the oxygen evolution reaction(OER)is of great importance. Herein, four cobalt porphyrins and corroles are deposited on electrode substrates using a simple and fast electropolymerization method. Our results showed that Co-1-P@CC, formed by electropolymerizing Co tetrakis(p-N-pyrrolylphenyl)porphyrin(Co-1-P) on carbon cloth(CC), is the most active OER catalyst in the examined Co porphyrins and corroles in alkaline aqueous solutions by displaying an onset overpotential of 380 m V. Long-term electrolysis tests confirmed the stability of these electropolymerized films by functioning as OER electrocatalysts.
基金Agency for ScienceTechnology and Research(IAF-PP A1789a0024, IAF-PP A19B3a0008)Robert Bosch(SEA) Pte. Ltd.
文摘Gas sensors have a wide variety of applications.Among various existing gas sensing technologies,optical gas sensors have outstanding advantages.The development of the Internet of Things and consumer electronics has put stringent requirements on miniaturized gas sensing technology.Here,we demonstrate a chip-scale silicon substrate-integrated hollow waveguide(Si-iHWG) to serve as an optical channel and gas cell in an optical gas sensor.It is fabricated through silicon wafer etching and wafer bonding.The Si-i HWG chip is further assembled with an off-chip light source and detector to build a fully functional compact nondispersive infrared(NDIR) CO_(2) sensor.The chip size is 10 mm × 9 mm,and the dimension of the sensor excluding the microcontroller board is 50 mm × 25 mm × 16 mm.This chip solution with compactness,versatility,robustness,and low cost provides a cost-effective platform for miniaturized optical sensing applications ranging from air quality monitoring to con-sumer electronics.
基金supported by the National Natural Science Foundation of China (Grant No.50771049)
文摘Microstructure and mechanical properties of an extruded Mg-2Dy-0.5Zn （at.%） alloy during isothermal ageing at 180℃ were investigated. Microstructure of the as-extruded alloy is mainly composed of α-Mg phase, 14H long period stacking order （LPSO） phase and small amounts of （Mg, Zn）=Dy particle phases. During ageing, the 14H LPSO phase forms and develops and its volume fraction increases with increasing ageing time. Tensile test showed that the peak-aged alloy exhibits similar yield and ultimate tensile strengths and elongation to failure at room temperature, 100℃ and 200℃, but excellent elevated temperature strengths at 300℃ as compared to the as-extruded and over-aged alloys. The analysis showed that the excellent elevated temperature strengths of the peak-aged alloy are attributed to the LPSO phase strengthening and the grain refinement strengthening, and the role of the LPSO strengthening is related to not only its amount, but also its morphology.
基金We are grateful for support from National Natural Science Foundation of China(21773146,22003036 and 22171176)Fok Ying-Tong Education Foundation for Outstanding Young Teachers in University,Fundamental Research Funds for the Central Universities(GK202103045 and GK202103033)Research Funds of Shaanxi Normal University,and the open fund of State Key Laboratory of Structural Chemistry.U.-P.A.thanks for the support by the Fraunhofer Internal Programs under Grant No.Attract 097-602175 and the DFG under Germany's Excellence Strategy-EXC-2033-Projektnummer 390677874“RESOLV”.
文摘Developing highly efficient electrocatalysts for the CO_(2) reduction reaction(CO_(2)RR)has attracted increasing interest in the past decade.Herein,we report on the design and synthesis of Fe porphyrin 1 with an appended N,N-di(2-picolyl)ethylenediamine(DPEN)unit that boosts electrocatalytic activity for CO_(2)-to-CO conversion in acetonitrile with water as the proton source.By mimicking carbon monoxide dehydrogenase(CODH),1 has poly-pyridine/amine units located at the active site to form hydrogen-bonded water-containing networks that enable fast proton transfer.The protonated and positively charged DPEN unit can also stabilize CO_(2) reduction intermediates through electrostatic and hydrogen-bonding interactions.These factors make 1 a highly active electrocatalyst for the CO_(2)RR by achieving a TOFmax of 5.0×10^(4)s^(−1) with water providing the protons.These critical roles of the DPEN unit in the CO_(2)RR are further supported by theoretical studies.This work is significant to highlight the benefits of using molecular catalysts to elucidate structural effects.
