Advanced oxidation processes (AOPs) based on sulfate radicals (SO4•-) are superior route for water treatment comparing to traditional AOPs, owing to their higher selectivity, longer half-life, and tolerance to wider pH range. To find an efficient source of SO4•-, peroxymonosulfate (PMS) molecules are widely used, which could be activated by the catalytic Fe(II) ions in traditional AOPs. However, this SO4•- -based catalytic activation method suffers from low conversion rate of Fe(III) to Fe(II), requires a large amount of catalytic Fe(II) ions, and produces a large amount of iron sludge as waste, which significantly limit its practical application for pollutants treatment. Herein, we show that by using molybdenum dioxide (MoO2) as a co-catalyst, the rate of Fe(III)/Fe(II) cycling reactions in the PMS system accelerated significantly, with a reaction rate constant 48 times that of conventional PMS/Fe(II) system. Our results showed outstanding removal efficiency (98%) of organic pollutant in 10 min with extremely low concentration of Fe(II) (0.036 mM), outperforming most reported SO4•--based AOPs systems. Additionally, MoO2 showed excellent stability and efficiency for wide range of pH values, recyclability for multiple activation cycles, practicality for removal of other organic compounds such as phenol and methylene blue. Surface chemical analysis combined with density functional theory (DFT) calculation demonstrated that both Fe(III)/Fe(II) cycling and PMS activation occurred on the (110) crystal plane of MoO2, while the exposed Mo4+ on the MoO2 surface are responsible for the co-catalyzing of iron ions to activate the PMS radicals. Considering its performance, low cost, and non-toxicity, using MoO2 as a co-catalyst in SO4•--based AOPs is a promising technique for large-scale practical environmental remediation.
The global push to keep global warming to less than 1.5 ºC, will require us to quickly adopt zero-emission energy carriers. Hydrogen, a versatile energy vector, is pivotal in this...
Abstract Herein, we show that copper nanostructures, if made anisotropic, can exhibit strong surface plasmon resonance comparable to that of gold and silver counterparts in the near‐infrared spectrum. Further, we demonstrate that a robust confined seeded growth strategy allows the production of high‐quality samples with excellent control over their size, morphology, and plasmon resonance frequency. As an example, copper nanorods (CuNRs) are successfully grown in a limited space of preformed rod‐shaped polymer nanocapsules, thereby avoiding the complex nucleation kinetics involved in the conventional synthesis. The method is unique in that it enables the flexible control and fine‐tuning of the aspect ratio and the plasmonic resonance. We also show the high efficiency and stability of the as‐synthesized CuNRs in photothermal conversion and demonstrate their incorporation into nanocomposite polymer films that can be used as active components for constructing light‐responsive actuators and microrobots.
Advanced oxidation processes (AOPs) based on sulfate radicals (SO4⋅−) suffer from low conversion rate of Fe(III) to Fe(II) and produce a large amount of iron sludge as waste. Herein, we show that by using MoO2 as a cocatalyst, the rate of Fe(III)/Fe(II) cycling in PMS system accelerated significantly, with a reaction rate constant 50 times that of PMS/Fe(II) system. Our results showed outstanding removal efficiency (96%) of L-RhB in 10 min with extremely low concentration of Fe(II) (0.036 mM), outperforming most reported SO4⋅−-based AOPs systems. Surface chemical analysis combined with density functional theory (DFT) calculation demonstrated that both Fe(III)/Fe(II) cycling and PMS activation occurred on the (110) crystal plane of MoO2, whereas the exposed active sites of Mo(IV) on MoO2 surface were responsible for accelerating PMS activation. Considering its performance, and non-toxicity, using MoO2 as a cocatalyst is a promising technique for large-scale practical environmental remediation.
Abstract Pristine titanium dioxide (TiO 2 ) changes color from white to black when it is reduced from Ti IV to Ti III by photoexcited electrons. However, the black coloration requires substantial light energy to create, and it vanishes instantaneously upon exposure to air. This work reports the synthesis of surface‐functionalized N‐doped TiO 2 nanocrystals that rapidly change color (i.e., within seconds) from whitish to black under low‐power irradiation with excellent color stability in atmospheric conditions. The N‐doping plays a critical role in promoting the surface‐adsorption of polyol groups to stabilize the Ti III species and accelerate the coloration process. A rewritable paper fabricated using these nanocrystals exhibits excellent writing and erasing reversibility in response to UV irradiation and oxygen exposure. The low‐cost, rapid response, excellent reversibility, and good color stability are vital advantages of N‐doped TiO 2 nanocrystals for color‐switching applications.
Abstract The fast and reversible switching of plasmonic color holds great promise for many applications, while its realization has been mainly limited to solution phases, achieving solid‐state plasmonic color‐switching has remained a significant challenge owing to the lack of strategies in dynamically controlling the nanoparticle separation and their plasmonic coupling. Herein, we report a novel strategy to fabricate plasmonic color‐switchable silver nanoparticle (AgNP) films. Using poly(acrylic acid) (PAA) as the capping ligand and sodium borate as the salt, the borate hydrolyzes rapidly in response to moisture and produces OH − ions, which subsequently deprotonate the PAA on AgNPs, change the surface charge, and enable reversible tuning of the plasmonic coupling among adjacent AgNPs to exhibit plasmonic color‐switching. Such plasmonic films can be printed as high‐resolution invisible patterns, which can be readily revealed with high contrast by exposure to trace amounts of water vapor.
Pristine titanium dioxide (TiO2 ) changes color from white to black when it is reduced from TiIV to TiIII by photoexcited electrons. However, the black coloration requires substantial light energy to create, and it vanishes instantaneously upon exposure to air. This work reports the synthesis of surface-functionalized N-doped TiO2 nanocrystals that rapidly change color (i.e., within seconds) from whitish to black under low-power irradiation with excellent color stability in atmospheric conditions. The N-doping plays a critical role in promoting the surface-adsorption of polyol groups to stabilize the TiIII species and accelerate the coloration process. A rewritable paper fabricated using these nanocrystals exhibits excellent writing and erasing reversibility in response to UV irradiation and oxygen exposure. The low-cost, rapid response, excellent reversibility, and good color stability are vital advantages of N-doped TiO2 nanocrystals for color-switching applications.
Corrosion and unwanted scales pose serious safety risks and financial costs in the oil and gas industry when they accumulate on pipelines and other critical infrastructure. Scale inhibitors (SIs) and corrosion inhibitors (CIs) injected into the system solve these issues. In addition, the application of separate chemicals for scale and corrosion necessitates astronomical costs for maintenance, including multiple storage containers, injection pumps, transportation pipelines, etc. In order to avoid this, SIs and CIs are frequently subjected to validation evaluations under simulation conditions prior to application on-site, which requires significant time and effort. By designing a multifunctional molecule with SI and CI functionality, which minimizes or eliminates incompatibility issues, new approaches have been proposed to resolve these problems. These scale and corrosion inhibitors (CSIs) have the potential to prevent scale formation and inhibit corrosion at the same time. Although the mechanism of action of SIs and CIs has been extensively investigated, the performance, benefits, and mechanism of action of CSIs have received less attention. This chapter focuses on the fundamentals of corrosion, scale formation and their inhibition, and co-injection issues involving separate inhibitors. Subsequently, the advantages of employing dual-purpose CSIs and recent research on dual-functional inhibitors are discussed.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)