Recent advancement on photocatalytic plastic upcycling.

More than 8 billion tons of plastics have been generated since 1950. About 80% of these plastics have been dumped in landfills or went into natural environments, resulting in ever-worsening contamination. Among various strategies for waste plastics processing (e.g., incineration, mechanical recycling, thermochemical conversion and electrocatalytic/photocatalytic techniques), photocatalysis stands out as a cost-effective, environmentally benign and clean technique to upcycle plastic waste at ambient temperature and pressure using solar light. The mild reaction conditions for photocatalysis enable the highly selective conversion of plastic waste into targeted value-added chemicals/fuels. Here, we for the first time summarize the recent development of photocatalytic plastic upcycling based on the chemical composition of photocatalysts (e.g., metal oxides, metal sulfides, non-metals and composites). The pros and cons of various photocatalysts have been critically discussed and summarized. At last, the future challenges and opportunities in this area are presented in this review.

Co-Cu Bimetallic Metal Organic Framework Catalyst Outperforms the Pt/C Benchmark for Oxygen Reduction.

Platinum (Pt)-based-nanomaterials are currently the most successful catalysts for the oxygen reduction reaction (ORR) in electrochemical energy conversion devices such as fuel cells and metal-air batteries. Nonetheless, Pt catalysts have serious drawbacks, including low abundance in nature, sluggish kinetics, and very high costs, which limit their practical applications. Herein, we report the first rationally designed nonprecious Co-Cu bimetallic metal-organic framework (MOF) using a low-temperature hydrothermal method that outperforms the electrocatalytic activity of Pt/C for ORR in alkaline environments. The MOF catalyst surpassed the ORR performance of Pt/C, exhibiting an onset potential of 1.06 V vs RHE, a half-wave potential of 0.95 V vs RHE, and a higher electrochemical stability (ΔE1/2 = 30 mV) after 1000 ORR cycles in 0.1 M NaOH. Additionally, it outperformed Pt/C in terms of power density and cyclability in zinc-air batteries. This outstanding behavior was attributed to the unique electronic synergy of the Co-Cu bimetallic centers in the MOF network, which was revealed by XPS and PDOS.

Investigating the UV absorption capabilities in novel Ag@RGO/ZnO ternary nanocomposite for optoelectronic devices.

A facile one-pot method was utilized at room-temperature for the synthesis of novel ternary nanocomposite of Ag@RGO/ZnO, which is introduced as a low cost, efficient and reliable UV absorber. The crystalline, morphological, structural, and optical characteristics of the as-synthesized samples were investigated by various techniques such as XRD, FE-SEM, HR-TEM, XPS, and DRS. The measurements confirm the successful fabrication of the Ag@RGO/ZnO ternary nanocomposite. Optical characterization showed the synergetic role of Ag NPs and RGO NSs in the enhancement of the light absorption of the ternary nanocomposite in the UV portion compared to the bare ZnO NPs. Additionally, band-gap narrowing was observed due to the Ag-doping impact where potential applications for the proposed nanocomposite have been suggested.

Novel Z-Scheme/Type-II CdS@ZnO/g-C3N4 ternary nanocomposites for the durable photodegradation of organics: Kinetic and mechanistic insights.

Visible-light-driven photocatalysis is a green and efficient strategy for wastewater treatment, where graphitic carbon nitride-based semiconductors showed excellent performance in this regard. Consequently, we report on the development of a green and facile one-pot room-temperature ultrasonic route for the preparation of novel ternary nanocomposite of cadmium sulfide quantum dots (CdS QDs), zinc oxide nanoparticles (ZnO NPs), and graphitic carbon nitride nanosheets (g-C3N4 NSs). The proposed materials had been characterized by several physicochemical techniques such as PXRD, XPS, FE-SEM, HR-TEM, PL, and DRS. The photocatalytic efficiency of the proposed photocatalysts was assessed towards the photodegradation of Rhodamine B dye as a water pollutant model using spectrophotometric measurements. The as-synthesized novel ternary nanocomposite (CdS@ZnO/g-C3N4) exhibited perfect photocatalytic activity, where almost complete degradation was achieved in only 2 h under UV-irradiation or 3 h under visible-irradiation. Various methods were used to elucidate the kinetics of the photocatalytic process. Moreover, CdS@ZnO/g-C3N4 exhibited a unique synergetic performance when compared to the corresponding binary composites or the individual components. This synergetic performance could be ascribed to the perfect electronic band configuration of the three components, leading to the establishment of several combined synergetic Z-Scheme/Type-II photocatalytic heterojunctions, which is the proposed mechanism for the observed synergetic photocatalytic reactivity of the as-synthesized CdS@ZnO/g-C3N4 nanocomposite when compared to the single and binary nanocomposite counterparts. Furthermore, the effects of both the type and concentration of various scavengers on the photocatalytic activity were assessed to investigate the most reactive species, where the reductive degradation pathway was found to be the predominant route. Finally, the photocatalytic efficiency of the as-synthesized CdS@ZnO/g-C3N4 composite showed promising and competing results when compared to other photocatalysts reported in the literature.

A graphene gold nanocomposite-based 5-FU drug and the enhancement of the MCF-7 cell line treatment.

There is no doubt that cancer is now one of the most formidable diseases in the world; despite all the efforts and research, common treatment routes, including chemotherapy, photodynamic therapy, and photothermal therapy, suffer from different limitations in terms of their efficiency and performance. For this reason, different strategies are being explored to improve the efficiency of the traditional drugs reported to date. In this study, we have redirected the function of one of these drugs (5-fluorouracil, 5-FU) by combining it with a graphene-gold nanocomposite in different molar ratios that has been exceedingly used for biological research development. The high activity of the graphene-gold material enables it to produce reactive oxygen and ions, which display good anticancer and antioxidant activity through the scavenging of the DPPH, SOD and GP x radicals; in addition, different characterizations have been used to confirm the structure and morphology of the obtained samples. Highly potent cytotoxicity against the MCF-7 cells was achieved with the drug combination containing the nanocomposite. All the results, including those obtained via cytometry, indicate that the combination of 5% graphene-gold nanocomposites with 5-FU exhibits a higher antitumor impact and more drug stability than pure 5-FU.