金属碳化钨与液相染料光敏剂协同促进光催化制氢

使用WC作为光催化材料通过水还原制氢很常见,但它通常需要与有效的光吸收剂协同才能产生有意义的光催化活性。这可归因于WC的窄带隙,导致水的氧化还原能力不足。有趣的是,我们的研究通过一种新型固液光催化体系克服了这种限制,该体系将裸WC光催化剂与液相光敏赤藓红B(Er B)相结合。这种概念的提出消除了将WC耦合到光吸收半导体的需要,这通常需要繁琐的程序来获得适当的功能化光催化复合材料。实验结果表明,在可见光(λ=520 nm)照射下,所提出的固液光催化体系产生了显著的氢气,然而,只有在三乙醇胺(TEOA)作为牺牲试剂的共同存在下。显然,仅加入WC和Er B的空白实验在典型的光催化条件下表现出几乎为零的光催化活性和无法测量的H_(2)生成。在光照TEOA溶液中仅存在Er B或WC的光反应中也观察到类似的活性。这些空白实验证实了所有三种成分的重要性,即WC、Er B和TEOA,它们分别作为光催化剂、光吸收剂和牺牲试剂,在我们提出的体系中产生有意义的H_(2)。值得注意的是,在我们的调查中系统地研究了三个关键参数,即p H值、Er B和WC浓度的影响。发现H_(2)生成的最佳p H值为8,稍微改变到更碱性或酸性条件会降低体系的光催化活性。在p H<8时,部分TEOA将发生部分质子化,从而失去其在光催化体系中作为牺牲试剂的活性。当p H值增加到超过8时,反应介质中的低质子浓度也会扰乱热力学驱动,导致体系产生的H_(2)受到抑制。同时,发现最佳Er B浓度为1mmol·L^(-1),从最佳点降低或增加Er B浓度均不利于H_(2)的产生。Er B浓度较低的体系(<1mmol·L^(-1)),在吸光上不足以满足体系的礼用,而较高浓度(>1 mmol·L^(-1)Er B)的体系,会引起明显的散射效应,组织光穿透反应溶液。相反,WC的浓度与H_(2)的生成呈稳定的正相关,在加入12 mmol·L^(-1)WC的体系中,H_(2)的生成量最高。在最佳条件下,成功生成了66μmol·h^(-1)H_(2),AQE略高为6.6%在520 nm处,这归因于Er B-TEOA-WC在所提出的体系中的协同作用。光电化学评估证实了Er B、TEOA和WC之间的相互作用,从而降低了阻抗,同时提高了体系中的电荷利用率。因此,还记录到了极好的H_(2)转换数(TON)为15,在至少20 h的连续反应中具有难以察觉的活性衰减。对于机理,密度泛函理论(DFT)计算进一步证实了W和C空位在H_(2)生成中的主要作用,这归因于他们提供的产品解吸,在光反应期间提高转化速率。从这些发现中得出结论,我们提出的新型WC/Er B/TEOA体系在液固光催化体系提供了一种更容易从水中产生H_(2)的策略,这为金属碳化物光催化剂避免选择繁琐的光吸收剂耦合。

Advances in particulate matter filtration:Materials,performance,and application

Air-borne pollutants in particulate matter(PM)form,produced either physically during industrial processes or certain biological routes,have posed a great threat to human health.Particularly during the current COVID-19 pandemic,effective filtration of the virus is an urgent matter worldwide.In this review,we first introduce some fundamentals about PM,including its source and classification,filtration mechanisms,and evaluation parameters.Advanced filtration materials and their functions are then summarized,among which polymers and MOFs are discussed in detail together with their antibacterial performance.The discussion on the application is divided into end-of-pipe treatment and source control.Finally,we conclude this review with our prospective view on future research in this area.

Surface plasmon resonance metal-coupled biomass carbon modified TiO_(2) nanorods for photoelectrochemical water splitting

Exploring efficient and stable photoanode materials is a necessary link to realize the practical application of solar-driven photoelectrochemical(PEC)water splitting.Hence,we prepared rutile TiO_(2) nanorods,with a width of 50 nm,which was growth in situ on carbon cloth(TiO_(2)@CC)by hydrothermal reaction.And then,Ag nanoparticles(NPs)and biomass N,S-C NPs were chosen for the additional modification of the fabricated TiO_(2) nanorods to produce broccoli-like Ag-N,S-C/TiO_(2)@CC nanocomposites.According to the result of ultraviolet-visible diffuse reflectance spectroscopy(UV-vis)and PEC water splitting performance tests,Ag-N,S-C/TiO_(2)@CC broadens the absorption region of TiO_(2)@CC from the ultraviolet region to the visible regio n.Under AM 1.5 G solar light irradiation,the photocurrent density of Ag-N,S-C/TiO_(2)@CC is 89.8μA·cm^(-2),which is 11.8 times higher than TiO_(2)@CC.Under visible light irradiation,the photocurrent density of Ag-N,S-C/TiO_(2)@CC reaches to 12.6μA·cm^(-2),which is 21.0 times higher than TiO_(2)@CC.Moreover,Ag-N,S-C/TiO_(2)@CC shows a photocurrent responses in full pH range.It can be found that Ag NPs and N,S-C NPs play key roles in broaden the absorption range of TiO_(2) nanorods to the visible light region and,promote the occurrence of PEC water oxidation reaction due to the surface plasmon resonance effect of Ag NPs and the synergistic effect of N,S-C NPs.The mechanism demonstrated that Ag-N,S-C/TiO_(2)@CC can separate the photogenerated electron-hole pairs effectively and transfer the photogenerated electrons to the photocathode(Pt plate)in time.This research provides a new strategy for exploration surface plasma metal coupled biomass carbon materials in the field of PEC water splitting.

Multifunctional hydrophobic fabric-based strain sensor for human motion detection and personal thermal management

Multifunctional flexible devices for human motion detection and thermal management raised great at-tention as the problem of the aging population is becoming more and more serious.However,it is still a challenge to endow the devices with excellent stability and wide application scope.Here we prepared a hydrophobic and conductive fabric-based strain sensor for smart fabric via successively coating with poly-dopamine(PDA),polyaniline(PANI),polypyrrole(PPy),and polydimethylsiloxane(PDMS)through in-situ polymerization and dip-coating,which could be used for strain sensor and wearable heater both in air and underwater.The obtained sample exhibited a fast electrical response in 500 ms and could withstand 10,000 times stretching-releasing cycles,additionally,the sample exhibited satisfactory electro-thermal and photo-thermal performances.As a whole,the multifunctional fabric-based devices with excellent performances show great potential to be applied in medical monitoring and personal care,especially for aged and disabled persons.

Rational designed ZIF-8@PDA@PDMS composite sponge for efficient and sustainable particulate matter filtering under harsh environment

Particulate matter(PM)is a significant danger to both environment and human health.Despite the development of a series of air filters,they do not work well in harsh environment such as high tem-perature,high humidity or long-time filtration.To make a three-dimensional(3D)particle capture de-vice,a sacrificial template approach was used to manufacture polydimethylsiloxane(PDMS)sponge,and then zeolite imidazole framework-8(ZIF-8)was grown in situ on the 3D network of PDMS sponge.The removal efficiency of PM_(2.5)or PM10 is greater than 99.8%because of the high specific surface area and porous network structure of PDMS sponge,as well as the large number of metal sites of ZIF-8.In addition,the sponge filter has long-term filtration stability and still achieves excellent performance after 65 h of filtration.The composite sponge can adapt to harsh environments such as high temperature(250℃)and high humidity(90%RH).Composite sponge filter has a regular shape,and it may be customized to any shape as required.This study provides a new idea for designing 3D high-efficiency air filters that can adapt to harsh environments.