Integrating photocatalytic reduction of CO2 with selective oxidation of tetrahydroisoquinoline over InP–In2O3 Z-scheme p-n junction

The development of a facile strategy to construct stable hierarchal porous heterogeneous photocatalysts remains a great challenge for efficient CO2 reduction.Additionally,hole-trapping sacrificial agents(e.g.,triethanolamine,triethylamine,and methanol)are mostly necessary,which produce useless chemicals,and thus cause costs/environmental concerns.Therefore,utilizing oxidation ability of holes to develop an alternative photooxidation reaction to produce value-added chemicals,especially coupled with CO2 photoreduction,is highly desirable.Here,an in situ partial phosphating method of In2O3 is reported for synthesizing In P–In2O3 p-n junction.A highly selective photooxidation of tetrahydroisoquinoline(THIQ)into value-added dihydroisoquinoline(DHIQ)is to replace the hole driven oxidation of typical sacrificial agents.Meanwhile,the photoelectrons of In P–In2O3 p-n junction can induce the efficient photoreduction of CO2 to CO with high selectivity and stability.The evolution rates of DHIQ and CO are 2 and 3.8 times higher than those of the corresponding In2O3 n-type precursor,respectively.In situ irradiated X-ray photoelectron spectroscopy and electron spin resonance are utilized to confirm that the direct Z-scheme mechanism of In P–In2O3 p-n junction accelerate the efficient separation of photocarriers.

Metal-organic frameworks-derived hierarchical ZnO structures as efficient sensing materials for formaldehyde detection

Semiconducting metal oxides have been considered as effective approach for designing highperformance chemical sensing materials.In this paper,a kind of metal-organic frameworks ZIF-8 was used as sacrificed template to prepare porous ZnO hollow nanocubes for the application in gas sensing.It is found that changing calcination temperature and solvent can greatly influence the morphology of the material,which finally affects the gas sensing performance.Acetylene-sensing properties of the sensors were investigated in detail.It can be clearly seen that the material used methanol as reaction solvent with the decomposition at 350℃for 2 h(ZnO-350-M)showed the optimal formaldehyde-sensing behaviors compared with other materials prepared in this experiment.The dynamic transients of the ZnO-350-M-based sensors demonstrated a high response value(about 10),fast response and recovery rate(4 s and 4 s,respectively)and good selectivity towards 100 ppm(part per million)formaldehyde as well as a low detectable limit(1 ppm).As exemplified for the sensing inve stigation towards formaldehyde,the porous ZnO hollow nanocubes showed a significantly improved chemical sensitivity due to the highly syne rgistic effects from the well exposed surfaces,defect states and the robust ZnO.

Design of tooth color measurement system based on silicon double P-N junction color sensor

Working principles of silicon double P-N junction color sensor are introduced and a color measurement system to distinguish tooth color difference is designed in this paper.This system consists of silicon double P-N junction,a small optical fiber probe,signal process circuit and an MSP430FG439 single-chip system.Small in size,this system can measure different parts of the tooth in a fast and convenient way with high-accuracy.Thus,this system will be very promising in building prosthodontics and tooth fabrication.