RSC Advances

Li, Zhenshan; Li, Qi; Jiang, Rong; Qin, Yan; Luo, Yan; Li, Jinsong; Kong, Wei; Yang, Zhiguo; Huang, Chao; Qu, Xin; Wang, Tao; Cui, Lin; Wang, Gang; Yang, Shengchao; Liu, Zhiyong; Guo, Xuhong

doi: 10.1039/d1ra08376gpmid: 35425559

Cu(II) ions are one of the most common forms of copper present in water and can cause bioaccumulation and toxicity in the human body; therefore, sensitive and selective detection methods are required. Herein, a copper ion sensor based on a UiO-66-NH2/ZnO composite material is proposed. The UiO-66-NH2/ZnO nanocomposite was prepared by an ultrasonic mixing method. The morphology and structure of the nanocomposite were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The sensitivity to Cu(II) is 6.46 μA μM−1 and the detection limit is 0.01435 μM. The composite material is rich in –OH and –NH2 groups, which are active sites for Cu(II) adsorption. The UiO-66-NH2/ZnO-modified electrode has good repeatability and anti-interference ability. The sensor was successfully used for the determination of Cu(II) in an actual water sample.

Zhan, Tao; Feng, Xiao-Zhen; An, Qi-Qi; Li, Shiyong; Xue, Mingyue; Chen, Zhencheng; Han, Guo-Cheng; Kraatz, Heinz-Bernhard

doi: 10.1039/d1ra09213hpmid: 35425584

Gold electrodes (GE) were modified by the deposition of copper nanoparticles (CuNPs) and cobalt nanoparticles (CoNPs), followed by drop-casting of the ferrocene derivative FcCO-Glu-Cys-Gly-OH (Fc-ECG), resulting in two enzyme-free electrochemical sensors Fc-ECG/CuNPs/GE and Fc-ECG/CuNPs/GE. The ferrocene-peptide conjugate acts as an effective redox mediator for glucose oxidation, while metal nanoparticles acted as non-biological sites for glucose oxidation. Field emission scanning electron microscopy (FESEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out for characterization, while differential pulse voltammetry (DPV) was used for glucose quantification. Under optimized conditions, DPV shows a linear relationship between glucose concentration and the peak current. Both sensors showed a surprisingly high sensitivity of 217.27 and 378.70 μA mM−1 cm−2, respectively. A comparison to other glucose sensors shows a sensitivity that is 25 times higher. The sensors exhibit good reproducibility, stability, and repeatability. In injection experiments, recovery rates were 87.39–107.65% and 100.00–106.88%, respectively.

Spear, Alyssa; Schuarca, Robson L.; Bond, Jesse Q.; Korter, Timothy M.; Zubieta, Jon; Doyle, Robert P.

doi: 10.1039/d1ra08261bpmid: 35425589

Optimized photocatalytic conversion of CO2 requires new potent catalysts that can absorb visible light. The photocatalytic reduction of CO2 using rhenium(I) has been demonstrated but suffers from low turnover. Herein, we describe a [Re(CO)3(1-(1,10)phenanthroline-5-(4-nitro-naphthalimide))Cl] photocatalyst, which when combined with the sacrificial donor 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole, results in selective production of formic acid and a high turnover number of 533 and turnover frequency of 356 h−1. Single-crystal X-ray diffraction and DFT studies are also discussed.

Atif, Muhammad; Naeem, Muhammad; Karim, Ramzan Abdul; Ameen, Faiza; Mumtaaz, Muhammad Waseem

doi: 10.1039/d1ra08331gpmid: 35425586

Carbon fillers have been a source of inspiration to accommodate a range of surface chemistries for different applications. In this study different surface chemistries have been compared for shape memory effect on polymeric composites. Sugar industry waste (fly ash) has been utilized to prepare carbon particles named FCB. Surface modification of FCB has been done in two steps, oxidation and thiolation, respectively. In the first step, different reagents have been used to anchor the surface of FCB with oxygenated functionalities. In the second step, oxygenated FCB has been treated with a thiolating agent to covalently link thio groups on its surface. Polymeric composites have been photo cured with both types of particles, separately. A thermal actuation study has been carried out to check the shape recovery behavior of the composites. A quick shape recovery has been observed for thiolated FCB composites, due to thio linkages in the polymeric network. Samples have been characterized by scanning electron microscopy (SEM), attenuated total reflectance (ATR), dynamic light scattering (DLS), thermal gravimetric analysis (TGA), pH, conductivity, acid content particle dispersion, and composite gel content.

Okazaki, Yuichi; Oda, Seiji; Takamatsu, Akihiko; Kawaguchi, Shogo; Tsukasaki, Hirofumi; Mori, Shigeo; Yagi, Shunsuke; Ikeno, Hidekazu; Yamada, Ikuya

doi: 10.1039/d2ra00448hpmid: 35425573

The rational design principle of highly active catalysts for the oxygen evolution reaction (OER) is desired because of its versatility for energy-conversion applications. Postspinel-structured oxides, CaB2O4 (B = Cr3+, Mn3+, and Fe3+), have exhibited higher OER activities than nominally isoelectronic conventional counterparts of perovskite oxides LaBO3 and spinel oxides ZnB2O4. Electrochemical impedance spectroscopy reveals that the higher OER activities for CaB2O4 series are attributed to the lower charge-transfer resistances. A density-functional-theory calculation proposes a novel mechanism associated with lattice oxygen pairing with adsorbed oxygen, demonstrating the lowest theoretical OER overpotential than other mechanisms examined in this study. This finding proposes a structure-driven design of electrocatalysts associated with a novel OER mechanism.

Arif, Muhammad; Shahid, Muhammad; Irfan, Ahmad; Nisar, Jan; Wu, Weitai; Farooqi, Zahoor H.; Begum, Robina

doi: 10.1039/d1ra09380kpmid: 35425556

Polymer microgels containing a polystyrene core and poly(N-isopropylmethacrylamide) shell were synthesized in aqueous media following a free radical precipitation polymerization. Au nanoparticles were fabricated into the shell region of the core–shell microgels denoted as P(STY@NIPM) by the in situ reduction of chloroauric acid with sodium borohydride. Various characterization techniques such as transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV-visible) and Fourier transform infrared spectroscopy (FTIR) were used for the characterization of Au–P(STY@NIPM). The catalytic potential of Au–P(STY@NIPM) toward the reductive reaction of 4-nitrophenol (4NP) under various reaction conditions was evaluated. The Arrhenius and Eyring parameters for the catalytic reduction of 4NP were determined to explore the process of catalysis. A variety of nitroarenes were converted successfully into their corresponding aminoarenes with good to excellent yields in the presence of the Au–P(STY@NIPM) system using NaBH4 as a reductant. The Au–P(STY@NIPM) system was found to be an efficient and recyclable catalyst with no significant loss in its catalytic efficiency.

Sahoo, Nirvik; Tatrari, Gaurav; Tewari, Chetna; Karakoti, Manoj; Bohra, Bhashkar Singh; Danadapat, Anirban

doi: 10.1039/d1ra07458jpmid: 35425562

We report the bulk phase synthesis of graphene sheets using waste plastic (WP) as a precursor following a modified pyrolysis approach. Furthermore, the low and high mass loading of vanadium pentaoxide was performed on graphene sheets in 1 : 10 and 1 : 1 ratios, respectively. Advanced characterization techniques such as Raman spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA) analysis, and SEM imaging were used to confirm the synthesis of graphene. FT-IR spectroscopy confirmed that the resonating structure affects the bond strength in the composite, which enables peak shifting in the FT-IR spectrum of the composite. Furthermore, bandgap analysis has been performed using UV-Vis spectroscopy, which confirmed the synthesis of the composites. The developed vanadium-doped graphene was used as the active material for the fabrication of supercapacitor electrodes. The electrochemical performance of these devices was evaluated in 1 M H3PO4 solution using cyclic voltammetry (CV), galvanic charge–discharge (GCD) analysis, and electrochemical impedance spectroscopy (EIS). Fabricated cells 1 and 2 showed exceptional specific capacitances of 139.7 F g−1 and 51.2 F g−1 at 5 mV s−1 scan rate, respectively. Cell 1 showed a huge power density of 5312 W kg−1 and an energy density of 19.7 W h kg−1. Conversely, cell 2 showed a comparatively lower power density of 1941 W kg−1 and an energy density of 7.2 W h kg−1 at a 5 mV s−1 scan rate. Moreover, we disclose some brief conclusions on the performance, mechanism, and required modifications that can improve the performance of such devices. This approach can surely help with universal WP problems as well as the development of high-performance supercapacitors.

Xin, Shihao; Peng, Xinxin; Zhang, Yao; Zheng, Aiguo; Xia, Changjiu; Lin, Min; Zhu, Bin; Huang, Zuoxin; Shu, Xingtian

doi: 10.1039/d1ra08501hpmid: 35425581

A tungsten containing catalyst catalyzed oxidative cleavage of methyl oleate (MO) by employing H2O2 as an oxidant and is known as an efficient approach for preparing high value-added chemicals, however, the tungsten leaching problem remains unresolved. In this work, a binary catalyst consisting of tungsten oxide (WO3) and spongy titanosilicate (STS) zeolite is proposed for MO oxidative cleavage. The function of STS in this catalyst is investigated. On the one hand, STS converts MO to 9,10-epoxystearate (MES), which further forms nonyl aldehyde (NA) and methyl azelaaldehydate (MAA) with the catalysis of WO3. In this way, MO oxidation and hydrolysis that generates unwanted diol product 9,10-dihydroxystearate (MDS) decreases obviously. On the other hand, STS decomposes peroxide and promotes the conversion of soluble peroxotungstate to insoluble polytungstate. Meanwhile, these tungsten species are allowed to precipitate on its surface instead of remaining in the liquid phase owing to its relative large specific area. Therefore, tungsten leaching can be reduced from 37.0% to 1.2%. Due to the cooperation of WO3 and STS, 94.4% MO conversion and oxidative cleavage product selectivity of 63.1% are achieved, and the WO3–STS binary catalyst maintains excellent catalytic performance for 8 recycling reactions.

Czupryński, Piotr; Płotka, Maciej; Glamowski, Piotr; Żukowski, Witold; Bajda, Tomasz

doi: 10.1039/d1ra09426bpmid: 35425530

The paper presents the results of a pilot-scale study investigating the efficiency of an ion exchange resin system in the removal of Ni, Hg, and Cr from flue gas desulphurisation wastewater, in the presence of competitive metals such as Ca, Mg, Al, Fe, and Mn. The core part of the ion exchange installation consisted of two columns that were filled with ion exchange resin with iminodiacetic functional groups (Purolite S930) and one column filled with resin with isothiouronium functional groups (Purolite S920). The results showed that Ni, Hg, and Cr were almost completely removed from the wastewater with nearly 100% efficiency. Purolite S930 almost totally removed Ni, reducing its content from 89.3 ± 35 μg dm−3 to below 0.1 μg dm−3, while Purolite S920 reduced the remaining Cr content from 2.2 ± 0.6 μg dm−3 and most of the Hg content, from 23.5 ± 6.6 μg dm−3 to below 0.1 μg dm−3. The competitive metals Ca, Mg, Mn, and Al showed low affinity to the studied ion exchange resins. The study also assessed speciation of ion forms and sorption mechanisms. Breakthrough curve analysis was also carried out, which revealed that the selectivity sequence of iminodiacetic resin was Ni > Cr > Hg > Fe > Al > Mn > Ca, Mg. Elution studies were performed on S930 resins that allowed the separation of two streams: one containing mostly Ni and Fe which can be subjected to Ni recovery and the other containing mostly Cr and Hg which can be separated.

Zhang, Xiaojuan; Gong, Meihua; Dai, Yunliang; Wen, Bianying

doi: 10.1039/d1ra09074gpmid: 35425555

A combination of a special micro–nanostructure and multiple components has been proven as an effective strategy to strengthen the microwave attenuation capacity. In this work, one-dimensional MoO2/N-doped carbon (NC) nanowires with a heterostructure have been successfully prepared by utilizing mild in situ chemical oxidative polymerization and pyrolysis treatment. After compounding them with a thermoplastic polyurethane (TPU) matrix, the flexible composites exhibit tunable wave absorbing performance by modulating the filler loading of MoO2/NC heteronanowires. Experimental results demonstrate that the minimum reflection loss value of the MoO2/NC–TPU hybrid is up to −35.0 dB at 8.37 GHz under a thickness of only 2.3 mm with 40 wt% filler amounts. Moreover, the effective absorption bandwidth enables 3.26 GHz to be achieved (8.49–11.75 GHz) when the thickness changes to 2.0 mm, covering almost the whole X-band. Meanwhile, when the filler loading becomes 30 wt%, dual-absorption peaks appear. The relevant absorption mechanism is mainly attributed to the dielectric loss including strong dipolar/interfacial polarizations, Debye relaxation loss and multiple reflection and scattering.