The high exciton binding energy and lack of a positive oxidation band potential restrict the photocatalytic CO_(2)reduction efficiency of lead-free Bi-based halide perovskites Cs_(3)Bi_(2)X_(9)(X=Br,I).In this study,a...The high exciton binding energy and lack of a positive oxidation band potential restrict the photocatalytic CO_(2)reduction efficiency of lead-free Bi-based halide perovskites Cs_(3)Bi_(2)X_(9)(X=Br,I).In this study,a sequential growth method is presented to prepare a visible-light-driven(λ>420 nm)Z-scheme heterojunction photocatalyst composed of BiVO_(4)nanocrystals decorated on a Cs_(3)Bi_(2)I_(9)nanosheet for photocatalytic CO_(2)reduction coupled with water oxidation.The Cs_(3)Bi_(2)I_(9)/BiVO_(4)Z-scheme heterojunction photocatalyst is stable in the gas-solid photocatalytic CO_(2)reduction system,demonstrating a high visible-light-driven photocatalytic CO_(2)-to-CO production rate of 17.5μmol/(g·h),which is approximately three times that of pristine Cs_(3)Bi_(2)I_(9).The high efficiency of the Cs_(3)Bi_(2)I_(9)/BiVO_(4)heterojunction was attributed to the improved charge separation in Cs_(3)Bi_(2)I_(9).Moreover,the Z-scheme charge-transfer pathway preserves the negative reduction potential of Cs_(3)Bi_(2)I_(9)and the positive oxidation potential of BiVO_()4.This study off ers solid evidence of constructing Z-scheme heterojunctions to improve the photocatalytic performance of lead-free halide perovskites and would inspire more ideas for developing leadfree halide perovskite photocatalysts.展开更多
The low separation efficiency of the photogenerated carrier and the poor activity of the surface redox reaction are the main barrier to further improvement of photocatalytic materials.To address these issues,introduci...The low separation efficiency of the photogenerated carrier and the poor activity of the surface redox reaction are the main barrier to further improvement of photocatalytic materials.To address these issues,introducing spin-polarized electrons in single-component photocatalytic materials emerged as a promising approach.However,the decreased redox ability of photocarriers in these materials becomes a new challenge.Herein,we mitigate this challenge with a carbon nitride sheet(CNs)/graphene nanoribbon(GNR)composite material that has a van der Waals heterostructures(vdWHs)and spin-polarized electron properties.Experimental results and theoretical calculations show that the heterostructure has a strong redox ability,high carrier-separation efficiency,and enhanced surface catalytic reaction.Consequently,the mixed-dimensional CNs/GNR vdWHs exhibit remarkable performance for H_(2)and O_(2)generation as well as CO_(2)production under visible-light irradiation without any cocatalyst.The spin-polarized vdWHs discovered in this study revealed a new type of photocatalytic materials and advanced the development of spintronics and photocatalysis.展开更多
In recent decades,the ozone layer has suffered considerable damage,increasing the entry of ultraviolet(UV)light into the atmosphere and reaching the earth’s surface,negatively affecting life.Accordingly,researchers a...In recent decades,the ozone layer has suffered considerable damage,increasing the entry of ultraviolet(UV)light into the atmosphere and reaching the earth’s surface,negatively affecting life.Accordingly,researchers aimed to solve this problem by synthesizing advanced UV-shielding materials.On the other hand,developing an easy and green strategy to prepare functional materials with outstanding properties based on naturally abundant and environmentally friendly raw materials is highly desirable for sustainable development.Because biomass-derived materials are sustainable and biodegradable,they present a promising substitute for petroleum-based polymers.The three main structural constituents of the plant biomass-based materials that are naturally available are cellulose,hemicellulose,and lignin.This review details current developments using wood-based products such as cellulose,hemicellulose,and lignin in UV-shielding applications.It will start with assembling the structure and chemistry of cellulose,hemicellulose,and lignin,followed by their contributions to preparing UV-shielding materials.Finally,it will briefly discuss the different processing methods for the design of UV-shielding materials.The wood by-products offer additional opportunities to use the whole tree harvest.展开更多
BACKGROUND Vitamin D deficiency is a common problem in exclusively breastfed infants,with supplementation recommended by various international medical organizations.However,in Thailand,no advice for routine vitamin D ...BACKGROUND Vitamin D deficiency is a common problem in exclusively breastfed infants,with supplementation recommended by various international medical organizations.However,in Thailand,no advice for routine vitamin D supplementation is available.Thus,this study investigated the prevalence of vitamin D deficiency and its associated factors in exclusively breastfed infants in Bangkok,Thailand.AIM To investigated the prevalence of vitamin D deficiency and its associated factors in exclusively breastfed infants in Bangkok,Thailand.METHODS This descriptive observational cross-sectional study assessed 1094-month-old infants at Charoenkrung Pracharak Hospital from May 2020 to April 2021.The 25-OH vitamin D level of the infants was measured using an electrochemiluminescence binding assay.Vitamin D deficiency was defined as 25-OH level<20 ng/mL,with vitamin D insufficiency 20-30 ng/mL.The sun index and maternal vitamin D supplementation data were collected and analyzed using the independent t-test,univariate logistic regression,and multivariate logistic regression to identify the associated factors.RESULTS The prevalences of vitamin D deficiency and vitamin D insufficiency were 35.78%and 33.03%,respectively with mean serum 25-OH vitamin D levels in these two groups 14.37±3.36 and 24.44±3.29 ng/mL.Multivariate logistic regression showed that the main factors associated with vitamin D status were maternal vitamin D supplementation and birth weight,with crude odds ratios 0.26(0.08–0.82)and 0.08(0.01–0.45),respectively.The sun index showed no correlation with the 25-OH vitamin D level in exclusively breastfed infants(r=−0.002,P=0.984).CONCLUSION Two-thirds of healthy exclusively breastfed infants had hypovitaminosis D.Vitamin D supplementation prevented this condition and was recommended for both lactating women and their babies.展开更多
基金support from the National Key R&D Plan Project(No.2022YFA1505000)Prospective Basic Research Projects of CNPC(Nos.2021DQ03(2022Z-29)+4 种基金2022DJ5406,2022DJ5407,2022DJ5408,2022DJ4507,and TGRI-2021-1)the Natural Science Foundation of Shaanxi Province(No.2022JQ-078)the Natural Science Foundation of China(No.52302308)the Outstanding Youth Science Foundation Project of the National Natural Science Foundation of China(Overseas)(No.GYKP033)the Qinchuangyuan Cited High-Level Innovative and Entrepreneurial Talents Project(No.QCYRCXM-2022-143).
文摘The high exciton binding energy and lack of a positive oxidation band potential restrict the photocatalytic CO_(2)reduction efficiency of lead-free Bi-based halide perovskites Cs_(3)Bi_(2)X_(9)(X=Br,I).In this study,a sequential growth method is presented to prepare a visible-light-driven(λ>420 nm)Z-scheme heterojunction photocatalyst composed of BiVO_(4)nanocrystals decorated on a Cs_(3)Bi_(2)I_(9)nanosheet for photocatalytic CO_(2)reduction coupled with water oxidation.The Cs_(3)Bi_(2)I_(9)/BiVO_(4)Z-scheme heterojunction photocatalyst is stable in the gas-solid photocatalytic CO_(2)reduction system,demonstrating a high visible-light-driven photocatalytic CO_(2)-to-CO production rate of 17.5μmol/(g·h),which is approximately three times that of pristine Cs_(3)Bi_(2)I_(9).The high efficiency of the Cs_(3)Bi_(2)I_(9)/BiVO_(4)heterojunction was attributed to the improved charge separation in Cs_(3)Bi_(2)I_(9).Moreover,the Z-scheme charge-transfer pathway preserves the negative reduction potential of Cs_(3)Bi_(2)I_(9)and the positive oxidation potential of BiVO_()4.This study off ers solid evidence of constructing Z-scheme heterojunctions to improve the photocatalytic performance of lead-free halide perovskites and would inspire more ideas for developing leadfree halide perovskite photocatalysts.
基金supported by the National Natural Science Foundation of China(Grant No.12104352 and 51973170)Fundamental Research Funds for the Central Universities(Grant No.XJS212208 and 2020BJ-56)+1 种基金Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(Grant No.2022-K67)the National Natural Science Foundation of Shaanxi Province under Grant No.2019JCW-17 and 2020JCW-15.
文摘The low separation efficiency of the photogenerated carrier and the poor activity of the surface redox reaction are the main barrier to further improvement of photocatalytic materials.To address these issues,introducing spin-polarized electrons in single-component photocatalytic materials emerged as a promising approach.However,the decreased redox ability of photocarriers in these materials becomes a new challenge.Herein,we mitigate this challenge with a carbon nitride sheet(CNs)/graphene nanoribbon(GNR)composite material that has a van der Waals heterostructures(vdWHs)and spin-polarized electron properties.Experimental results and theoretical calculations show that the heterostructure has a strong redox ability,high carrier-separation efficiency,and enhanced surface catalytic reaction.Consequently,the mixed-dimensional CNs/GNR vdWHs exhibit remarkable performance for H_(2)and O_(2)generation as well as CO_(2)production under visible-light irradiation without any cocatalyst.The spin-polarized vdWHs discovered in this study revealed a new type of photocatalytic materials and advanced the development of spintronics and photocatalysis.
文摘In recent decades,the ozone layer has suffered considerable damage,increasing the entry of ultraviolet(UV)light into the atmosphere and reaching the earth’s surface,negatively affecting life.Accordingly,researchers aimed to solve this problem by synthesizing advanced UV-shielding materials.On the other hand,developing an easy and green strategy to prepare functional materials with outstanding properties based on naturally abundant and environmentally friendly raw materials is highly desirable for sustainable development.Because biomass-derived materials are sustainable and biodegradable,they present a promising substitute for petroleum-based polymers.The three main structural constituents of the plant biomass-based materials that are naturally available are cellulose,hemicellulose,and lignin.This review details current developments using wood-based products such as cellulose,hemicellulose,and lignin in UV-shielding applications.It will start with assembling the structure and chemistry of cellulose,hemicellulose,and lignin,followed by their contributions to preparing UV-shielding materials.Finally,it will briefly discuss the different processing methods for the design of UV-shielding materials.The wood by-products offer additional opportunities to use the whole tree harvest.
基金Supported by Charoenkrung Pracharak Hospital,No.S008h/63.
文摘BACKGROUND Vitamin D deficiency is a common problem in exclusively breastfed infants,with supplementation recommended by various international medical organizations.However,in Thailand,no advice for routine vitamin D supplementation is available.Thus,this study investigated the prevalence of vitamin D deficiency and its associated factors in exclusively breastfed infants in Bangkok,Thailand.AIM To investigated the prevalence of vitamin D deficiency and its associated factors in exclusively breastfed infants in Bangkok,Thailand.METHODS This descriptive observational cross-sectional study assessed 1094-month-old infants at Charoenkrung Pracharak Hospital from May 2020 to April 2021.The 25-OH vitamin D level of the infants was measured using an electrochemiluminescence binding assay.Vitamin D deficiency was defined as 25-OH level<20 ng/mL,with vitamin D insufficiency 20-30 ng/mL.The sun index and maternal vitamin D supplementation data were collected and analyzed using the independent t-test,univariate logistic regression,and multivariate logistic regression to identify the associated factors.RESULTS The prevalences of vitamin D deficiency and vitamin D insufficiency were 35.78%and 33.03%,respectively with mean serum 25-OH vitamin D levels in these two groups 14.37±3.36 and 24.44±3.29 ng/mL.Multivariate logistic regression showed that the main factors associated with vitamin D status were maternal vitamin D supplementation and birth weight,with crude odds ratios 0.26(0.08–0.82)and 0.08(0.01–0.45),respectively.The sun index showed no correlation with the 25-OH vitamin D level in exclusively breastfed infants(r=−0.002,P=0.984).CONCLUSION Two-thirds of healthy exclusively breastfed infants had hypovitaminosis D.Vitamin D supplementation prevented this condition and was recommended for both lactating women and their babies.
