Nanocrystalline Iron Pyrophosphate-Regulated Amorphous Phosphate Overlayer for Enhancing Solar Water Oxidation

A rational regulation of the solar water splitting reaction pathway by adjusting the surface composition and phase structure of catalysts is a substantial approach to ameliorate the sluggish reaction kinetics and improve the energy conversion efficiency.In this study,we demonstrate a nanocrystalline iron pyrophosphate(Fe_(4)(P_(2)O_(7))_(3),FePy)-regulated hybrid overlayer with amorphous iron phosphate(FePO_(4),FePi)on the surface of metal oxide nanostructure with boosted photoelectrochemical(PEC)water oxidation.By manipulating the facile electrochemical surface treatment followed by the phosphating process,nanocrystalline FePy is localized in the FePi amorphous overlayer to form a heterogeneous hybrid structure.The FePy-regulated hybrid overlayer(FePy@FePi)results in significantly enhanced PEC performance with long-term durability.Compared with the homogeneous FePi amorphous overlayer,FePy@FePi can improve the charge transfer efficiency more significantly,from 60% of FePi to 79%of FePy@FePi.Our density-functional theory calculations reveal that the coexistence of FePi and FePy phases on the surface of metal oxide results in much better oxygen evolution reaction kinetics,where the FePi was found to have a typical down-hill reaction for the conversion from OH*to O_(2),while FePy has a low free energy for the formation of OH*.

Key Technology Research for Mobile Police Terminal Fingerprint Collection for Quick Comparison Using Automated Fingerprint Identification System

When the face of the inspected person and the photograph on their identification(ID)card cannot be clearly matched,the individual is undocumented,or the ID is forged,it is often difficult for the on‑site police to respond in time.This study proposes a number of key technologies for collecting fingerprints at mobile terminals for fast comparison using an automated fingerprint ID system(AFIS).These technologies ensure intelligent mobile fingerprint collection and allow the transmission of fingerprint information from the terminal to AFIS,over a wireless public security network for real‑time fingerprint comparison.This study also analyzes the feasibility and effectiveness of the proposed technologies for system design and the applicability of fingerprint ID algorithms.The system achieved good results in a test by the Shanghai Public Security Bureau Criminal Investigation Corps.

Far-infrared transparent conductors

The long-standing challenge in designing far-infrared transparent conductors(FIRTC)is the combination of high plasma absorption edge(λ_(p))and high conductivity(σ).These competing requirements are commonly met by tuning carrier concentration or/and effective carrier mass in a metal oxide/oxonate with low optical dielectric constant(ε_(opt)=2-7).However,despite the highσ,the transparent band is limited to mid-infrared(λ_(p)<5μm).In this paper,we break the trade-off between highσandλ_(p)by increasing the“so-called constant”ε_(opt)that has been neglected,and successfully develop the material family of FIRTC withε_(opt)>15 andλ_(p)>15μm.These FIRTC crystals are mainly octahedrally-coordinated heavy-metal chalcogenides and their solid solutions with shallow-level defects.Their highε_(opt)relies on the formation of electron-deficiency multicenter bonds resulting in the great electron-polarization effect.The new FIRTC enables us to develop the first“continuous film”type far-infrared electromagnetic shielder that is unattainable using traditional materials.Therefore,this study may inaugurate a new era in far-infrared optoelectronics.

Designing hard wear-resistant conductors by introducing high-plasma-energy heterogeneous metals into transition metal nitrides

1.Introduction Hard and wear-resistant conductors(HWCs)refer to functional films with simultaneously high hardness,high wear resistance,and good electrical conductivity.HWCs have important applica-tions such as next-generation sliding electrical contacts,high-end conductive probe-tip,and oval hole guides for the precision rolling mill[1-4],which has drawn extensive research interests.However,it is still challenging to integrate high hardness,super wear resis-tance,and high electrical conductivity in one material.Tradition-ally,researchers have mainly alloyed the highly conductive met-als Cu,Au,and Pt to improve their hardness and wear resistance.

New design for highly durable infrared-reflective coatings

The fundamental challenge in designing durable infrared-reflective coatings is achieving the ideal combination of both high reflectivity and durability.Satisfying these competing demands is traditionally achieved by deposition of durable layers on highly reflective metals.We overturn the traditional logic of‘first reflectivity and then durability’and propose an alternative of‘first durability and then reflectivity’:First,a transition-metal compound is selected as a durable base;then its reflectivity is improved by incorporating silver/gold to form an alloy or by overcoating a multilayer stack.Two validation experiments prove that the new strategy works extremely well:the coatings thus obtained have infrared reflectivities close to that of aluminum,and their hardness and acid and salt corrosion resistances are 27–50,400–1500 and 7500–25000 times that of aluminum.The traditional mirror coating(e.g.,Al/SiO2 films)is more suitable for moderate environments,while our mirror coating that was obtained by the new strategy(e.g.,an Ag-doped hafnium nitride film)is more suitable for harsh environments,such as ones with dust,windblown sand,moisture,acid rain or salt fog.This work opens up new opportunities for highly durable infrared-reflective coatings and rejuvenates the study of transition metal compounds in a completely new area of optics.