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Carbon nitride (C3N4) is a promising metal-free photocatalyst for solar-to-energy conversion, but bulk carbon nitride (BCN) shows insufficient light absorption, sluggish photocarrier transfer and moderate activity for photocatalysis. Herein, a facile strategy to significantly increase solar spectrum absorption of the functionalized porous carbon nitride nanosheets (MFPCN) via molecule self-assembly engineering coupled thermal polymerization is reported. This strategy can greatly enhance the wide-solar-spectrum absorption of MFPCN up to 1000 nm than most reported carbon nitride-based photocatalysts. Experimental characterizations and theoretical calculations together display that this strategy could introduce hydroxyl groups into the structure of MFPCN as well as the rich pores and active sites at the edges of framework, which can narrow the bandgap and accelerate the transfer and separation of photoinduced carries. As a result, the optimal MFPCN photocatalyst exhibit the excellent photocatalytic hydrogen evolution rate of 7.745 mmol g-1h−1 under simulated solar irradiation, which is ≈13 times that of BCN with remarkable durable CO2 reduction activities. New findings in this work will provide an approach to extend solar spectrum absorption of metal-free catalysts for solar fuel cascades.

Solution-processed polycrystalline perovskite films have detrimental defects in the bulk and surfaces/grain boundaries, especially the uncoordinated lead ions (Pb2+) with low formation energy, limiting both the performance and stability of the photovoltaic devices. In this work, a conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is incorporated into a bulk perovskite film by a facile in-situ polymerization method, where 5-bromo-2,3-dihydro-thieno[3,4-b] [1] , [4] dioxine (BEDOT) as monomer is directly added to a perovskite precursor solution and then in-situ polymerized within the perovskite film during the film formation. The PEDOT is chemically anchored at the surface and grain boundaries of the perovskite film via interaction of sulfur and oxygen atoms in PEDOT with uncoordinated lead ions in the perovskite, passivating the surface and bulk defects and also improving the charge extraction efficiency in the solar cell. Moreover, robust and hydrophobic properties of PEDOT can enhance the thermal and moisture resistance of the perovskite film. As a result, a champion power conversion efficiency (PCE) of 22.58% is achieved, along with significantly enhanced environmental, thermal, and light-soaking stability.

Developing a low-cost and efficient photocatalysts activated peroxymonosulfate (PMS) for organic pollutants degradation are recognized as an importance way for dealing with environmental pollution. In this work, Fe-rectorite catalyst was synthesized by a simple impregnation-calcine method to synergetic photo activate PMS for antibiotics degradation. As expected, the Fe-rectorite/PMS/Light system exhibits superior catalytic performance for tetracycline (TC) removal, which achieving 96.4% removal rate of TC (30 mg/L) under light within 60 min. Fe-retorite has better degradation performance for TC than rectorite under photo-mediation. The enhancement of the degradation performance of TC by Fe-retorite can be attributed to the improvement of the separation efficiency of photogenerated electrons and holes in the rectorite by the loading of Fe

Studies have received intense concern on the classical conductive polymers for thermoelectric (TE) materials; but polypyrrole (PPy) seemed to be an exception due likely to its relatively poor TE behaviors. In this work, we present an unconventional two-step electrochemical post-treatment strategy to improve the TE performance of the PPy films electrodeposited, namely first oxidation at + 0.7 V and subsequent reduction at different potentials ranged from − 1.3 to 0 V (vs Ag/Ag+). The doping level of PPy films was regulated accurately by controlling the applied potential. Consequently, the significantly enhanced power factor and figure of merit have been achieved, which are far higher than those of the films obtained via one-step electrochemical post-treatment and hit the records high for the pure PPy. This indicates that the two-step electrochemical post-treatment is a feasible and effective protocol for perfecting thermoelectric performance of polymers, and may be extended to other conducting polymeric systems.

Resourcing solid waste as catalysts for activating peroxymonosulfate (PMS) used in high-salt organic wastewater treatment, to realize waste control, is meaningful, promising, and a win–win strategy for environmental remediation. Here, a magnetically recyclable hybrid originating from used warm paste (greater than92% yield) was developed using water washing to activate PMS for antibiotics degradation under hypersaline system. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) measurements indicated that the hybrid is a sheet structure with active Fe sites uniformly dispersed on the surface. The hybrid displayed an excellent PMS activation capacity; it is superior to those of classical Fe3O4 and Co3O4, which could degrade the tetracycline (TC). However, under a high-salt (0.2 mol/L Na2SO4) or mixed salts condition, the hybrid exhibited TC degradation performance. Moreover, a detailed investigation of the impact on of TC removal indicated that the preferable conditions were pH = 6, temperature = 25 °C, catalyst = 0.3 g/L and PMS = 0.3 g/L. Systematic experiments uncovered the hybrid exhibiting superb catalysis universality and adaptability in three refractory organics, 5 natural polluted water matrices, and coexisting-ions system, as well as five times, recycle processes. The surface chemical analysis combined with quenching experiment and electron paramagnetic resonance (EPR) test confirmed the PMS activation mechanism and the reactive radicals contributed in order of 1O2 > •OH > SO4•−. Considering its performance, stability and applicability, the warm paste hybrid would be good for PMS activation toward high-salt environment remediation. Thus inducing a novel direction for solid waste treatment and mitigated resource scarcity.

Bimetallic catalyst with three-dimensional hierarchical structure is very promising for Fenton-like reaction owing to its synergistic effect and unique microstructure. The combination of photocatalysis with peroxymonosulfate (PMS) as a good electron acceptor is an effective method to avoid the combination of electrons and holes, further significantly improving the degradation efficiency of refractory organics. In this work, a three-dimensional hierarchical and spinel-type MnCo2O4 catalyst was studied as a proof of concept for effective photoinduced PMS activation towards antibiotics degradation. As expected, the three-dimensional hierarchical MnCo2O4 (3D MnCo2O4) catalyst showed an excellent catalytic activity for PMS activation towards tetracycline (TC) degradation under the light irradiation over MnO2/light/PMS systems, Co3O4/light/PMS systems and general MnCo2O4/light/PMS systems. In a wide pH range (3-9) and a complex anionic (Cl−, HCO3−, NO3− and PO43−) environment, the 3D MnCo2O4/PMS/light system also can still degrade 95% of TC within 15 min and keep good catalytic stability. The superiority of 3D MnCo2O4/PMS/light system towards efficiency of TC degradation is attributed to its synergistic effect of Co-Mn on Co (III)/Co (II) cycle, peculiar microstructure and photocatalysis combination. Our work provides a promising highly-efficient heterogeneous catalytic system for environmental application.

Developing a low-cost and excellent catalyst for advanced oxidation process (AOPs) to degrade refractory organic contaminants is still an urgent problem. In this work, a copper oxide decorated natural rectorite (Cu-R) catalyst was successfully synthesized by a facile impregnation method. Intriguingly, Cu-R possessed excellent performance in removing tetracycline (TC) through photoinduced peroxymonosulfate (PMS) activation, and its reaction rate constants were ca. 4.3 times and 7.0 times that of Fe2O3 and Co3O4, respectively. Moreover, the effects of reaction parameters on the photoinduced Cu-R activation of PMS to degrade TC were investigated in detail. The results showed that the system exhibited excellent impact resistance to Cl−, HCO3− and NO3− in aqueous solution. Cu-R could not only exhibit excellent removal of TC in a wide pH range of 5–9, but also maintain the stability of the catalyst. The electron paramagnetic resonance test and quenching experiments proved that the excellent TC removal ability could be mainly attributed to the synergistic effect between CuO and rectorite under the assistant of light, which was beneficial for the activation of PMS and then produced a large number of active radicals such as •OH and O2•-. Importantly, a possible path for TC degradation was given by the LC-MS analysis. The prepared Cu-R can provide a low-cost, high-efficiency and promising catalyst for the treatment of antibiotic wastewater by PMS activation with photoassistent.

Full light photo-Fenton and photo-thermal effect are of great importance but deserve attentions far insufficient in advanced oxidation progresses for extensive environmental remediation. Herein, ultraviolet-visible-near infrared (UV–vis-NIR) light absorbance and photo-thermal conversion were induced into H2O2 activation towards refractory antibiotics elimination from wastewater through green recyclable rGO-ZnFe2O4 developed via ultrasonic method. Interestingly, photo-thermal synergy presents much superior performance than that of solely photo-Fenton or thermal-Fenton process. Multiple light reflection inner ZnFe2O4 microsphere strengthens UV–vis capture and thermal conversion in degradation reaction. Orbital hybridization and electron rearrangement endow rGO-ZnFe2O4 wide NIR absorbency, fast thermal transfer and photo-generated electrons-holes separation for photo-thermal Fenton progress. Degradation rate of ciprofloxacin on rGO-ZnFe2O4 is found 3 times of ZnFe2O4 under full light exposure which can heat solution from room temperature to 70 °C, while 4 times under NIR irradiation where solution is heated to 46 °C. The great differences are mainly originated from photo-induced thermal energy, which in-situ heating active sites to lower H2O2 activation barrier, accelerate Fe2+/Fe3+ cycle and facilitate spread of radicals. Radicals contribute in OH > h+ > O2 − under full light irradiation, while perform in h+ > O2 − > OH when taking away photo-generated heat. Results based on systematic experiments and theory calculation imply the strong potential of photo-thermal Fenton in pollutants control, which proposes novel strategy in Fenton reaction for environmental remediation with effective utilization of solar energy.

A direct evidence by infrared dichroism is reported for the first time for the effect of molecular orientation on thermoelectric (TE) performance of organic polymer materials. The preferred orientation was induced by mechanical uni-axial stretching of the films of neat polyaniline (PANI) and its nanocomposites with reduced graphene oxide (rGO) or multi-walled carbon nanotube (MWCNT). Five characteristic bands of Fourier transform infrared (FTIR) spectra were chosen, and quantitative investigations were carried out using the dichroic ratios measured by polarized FTIR spectra. The influences of draw ratio and content of inorganic carbon nanoparticles were taken into account. The results show that the TE performance (including anisotropic TE function) can be conveniently tuned by polymer molecular orientation induced by mechanical stretching, which shed light on the understanding of molecular mechanism towards structure-TE performance relationship, and will speed up the applications of organic polymer TE materials.

Being green energy materials, thermoelectric (TE) materials can realize direct energy conversions between heat and electricity, thus have widely applications in both TE generators for energy harvesting and local cooling. Especially, low-quality waste heat can be conveniently used. In the recent several years, there is rapidly growing interest in organic conducting polymer/carbon particle TE composites, which synergistically combine the advantages of both carbon particles and polymer materials. In this review, the recent progress is systematically summarized in the order of the dimensionality of the carbon particles (2D, 1D and 0D) and the type of polymer matrix. Synergistic effect and polymer ordered structure, morphological tuning, devices and flexible films are highlighted. Finally, prospects and suggestions for future studies are presented.

The development of high activity, long stability, and cost-efficient catalyst for overall water splitting is paramount for the scalable production of hydrogen. Herein, we report low ruthenium content ruthenium cobalt nanoalloys encapsulated in nitrogen-doped carbon layers synthesized via incipient-wetness impregnation-pyrolysis method (denoted as RuCo@NC-temp.). A series of characterizations reveal that trace amounts of ruthenium inserts into the cobalt lattice matrix that can form RuCo alloys. The optimized catalyst (RuCo@NC-750, 1.56 wt% Ru) shows superior catalytic performance for hydrogen evolution reaction in alkaline, acidic, and neutral media, as well as oxygen evolution reaction in alkaline media. The catalytic reaction displays an overpotential of 25 mV (1.0 M KOH), 29 mV (0.5 M H2SO4), and 163 mV (1.0 M PBS) for hydrogen evolution reaction and 308 mV (1.0 M KOH) for oxygen evolution reaction at a current density of 10 mA cm−2. RuCo@NC-750 needs only 1.54 V to achieve a current density of 10 mA cm−2 when it serves as both the anode and cathode material in a two-electrode electrolyzer. The excellent electrocatalytic performance can be attributed to the doping of ruthenium into the cobalt lattice matrix, which effectively enhance the electron transfer from the metal core to the carbon surface, and is beneficial for regulating the electronic structure of the carbon surface and strengthening the carbon-hydrogen bond and surface defects.