2D/2D Ti_(3)C_(2) MXene/HTiNbO5 nanosheets Schottky heterojunction for boosting photothermal-assisted solar-driven photodegradation of tetracycline hydrochloride

Developing high-efficiency photocatalysts for tetracycline hydrochloride(TCH)degradation is of great sig-nificance to ecosystems and human beings.In this work,a two-step process of exfoliation and re-stacking was performed to prepare re-stacked HTiNbO_(5) nanosheets(R-HTNS)and then coupled with Ti_(3)C_(2) MXene to construct Ti_(3)C_(2) MXene/R-HTNS(MX/RTS)with a 2D/2D Schottky heterojunction.These 2D/2D het-erostructures between Ti_(3)C_(2) MXene and R-HTNS can produce an internal electric field and provide max-imum interface area for efficient charge transfer across the intimate interface.The photocatalytic perfor-mance of samples was evaluated by TCH degradation under simulated sunlight.The MX/RTS composites,with an optimal sample of 3-MX/RTS,show enhanced photocatalytic activity for TCH degradation com-pared with R-HTNS.The characterization results reveal that the introduction of Ti_(3)C_(2) MXene can signif-icantly increase specific surface area for providing more reactive sites and broaden the light absorption region.Besides,the incident light energy is absorbed by the Ti_(3)C_(2) MXene component in MX/RTS compos-ites to generate photothermal energy(heat),which facilitates the charge carrier separation and surface reaction kinetics.Thus,the enhanced TCH photodegradation activity for MX/RTS composites is due to the introduction of Ti_(3)C_(2) MXene,which possesses the synergistic effect of the increased specific surface area,improved light-harvesting capacity,2D/2D Schottky heterojunction,and photothermal energy effect.Additionally,the TCH photodegradation behavior is deliberated with a detailed discussion on various co-existing ions.During TCH photodegradation,the active radical species are determined for 3-MX/RTS.Ac-cording to the characterization results,the possible TCH photodegradation pathway and mechanism over 3-MX/RTS are explored.This work may offer a novel insight for constructing MXene-based heterostruc-tured photocatalysts with high efficiency.

多形态火焰高度的小区间光强分布检测

火焰高度是易燃化学品常规检测参数,其定量检测方法多采用人工比对或基于机器视觉的图像检测。前者受主观影响、危险性高,后者系统复杂、难以适应广谱多形态火焰,因此,提出了一种广谱火焰高度检测方法。该方法采用光热双传感器阵列配合梳状遮光装置划分火焰高度,消除相邻传感器非水平方向入射光线的干扰,并通过小区间光强分布计算进一步提高检测准确性。试验结果表明,该方法可实现广谱多形态火焰高度的准确、非接触、低成本检测,易于工程化实现。