Latest ArticlesHeterocyclic compounds play an important role in organic hole transport materials (HTMs) for perovskite solar cells (PSCs). Herein, a series of linear D-π-D HTMs (OCBz, S-CBz, SO2-CBz) with different dibenzo-heterocycles core (dibenzofuran, dibenzothiophene, dibenzothiophene sulfone) were designed and synthesized, and their applications in PSCs were investigated. The intrinsic properties (CV, UV–vis, hole mobility and conductivity) were systematically investigated, demonstrating that all three materials are suitable HTMs for planar n-i-p type PSCs. Benefiting from the excellent hole mobility and conductivity, good film forming ability, and outstanding charge extraction and transport capability of S-CBz, FAPbI3-based PSCs using S-CBz as HTM achieved a PCE of 25.0%, which is superior to that of Spiro-OMeTAD-based PSCs fabricated under the same conditions (23.9%). Furthermore, due to the interaction between S and Pb2+, S-CBz-based PSC devices exhibited improved stability. This work demonstrates that dibenzothiophene-based architectures are promising candidates for high-performance HTMs in perovskite solar cell architectures.
Two-dimensional (2D) transition metal sulfides (TMDs) are emerging and highly well received 2D materials, which are considered as an ideal 2D platform for studying various electronic properties and potential applications due to their chemical diversity. Converting 2D TMDs into one-dimensional (1D) TMDs nanotubes can not only retain some advantages of 2D nanosheets but also providing a unique direction to explore the novel properties of TMDs materials in the 1D limit. However, the controllable preparation of high-quality nanotubes remains a major challenge. It is very necessary to review the advanced development of one-dimensional transition metal dichalcogenide nanotubes from preparation to application. Here, we first summarize a series of bottom-up synthesis methods of 1D TMDs, such as template growth and metal catalyzed method. Then, top-down synthesis methods are summarized, which included self-curing and stacking of TMDs nanosheets. In addition, we discuss some key applications that utilize the properties of 1D-TMDs nanotubes in the areas of catalyst preparation, energy storage, and electronic devices. Last but not least, we prospect the preparation methods of high-quality 1D-TMDs nanotubes, which will lay a foundation for the synthesis of high-performance optoelectronic devices, catalysts, and energy storage components
Cu-based metal-organic frameworks (MOFs) are widely employed in CO2 reduction reactions (CO2RR). Mostly, the in-situ reconstructed derivatives such as Cu or Cu oxides during CO2RR are regarded as the catalytic active center for the formation of catalytic products. However, in many cases, the pristine MOFs still exist during the catalytic process, the key role of these pristine MOFs is often ignored in revealing the catalytic mechanism. Here, we designed two Cu(imidazole) with different coordination environments, namely CuN2 and Cu2N4 for CO2RR. The structures of the two MOFs were still remained after the catalytic reaction. We discovered that the pristine MOFs served as activation catalysts for converting CO2 into CO. Sequentially, the Cu-based derivatives, in the two cases, Cu(111) converted the CO into C2+ products. The CuN2 with more exposed Cu-N centers showed a higher FECO and a higher final FEC2+ than Cu2N4. This auto-tandem catalytic mechanism was supported by electrocatalytic performance, TPD-CO, HRTEM, SAED, XPS, in-situ XANES and XES and DFT computation. The auto-tandem catalytic mechanism provides a new route to design Cu-based MOF electrocatalysts for high product selectivity in CO2RR.
Green synthesis of drugs is of paramount importance for current public health and a prerequisite to new drugs exploiting. Nowadays, novel strategies of disease diagnosis and therapies are in blooming development as remarkable advances have been achieved which are all highly depended on drug development. Under the current requirements to high production capacity and novel synthesis methods of drugs, green synthesis based on strategies with different ways of empowering, advanced catalysts and unique reaction equipment are attracting huge attention and of great challenging. Higher quality products and environmentally friendly synthesis conditions are becoming more and more important for manufacturing process which has new requirements for catalyst materials and synthesis processes. Polyoxometalates (POMs) are class of transition metals-oxygen clusters with precise molecular structures and superior physicochemical properties which have made longstanding and important applications upon research community of functional materials, catalysis and medicine. In this review, the recent advances of polyoxometalates based strategies for green synthesis of drugs are summarized including POMs based catalysts, alternative reaction equipment based novel synthesis protocols. The significance of POMs to pharmaceutical and industrial field is highlighted and the related perspective for future development are well discussed.
Metal-organic frameworks (MOFs) provide great prospective in the photodegradation of pollutants. Nevertheless, the poor separation and recovery hamper their pilot- or industrial-scare applications because of their microcrystalline features. Herein, this challenge can be tackled by integrating Cu-MOFs into an alginate substrate to offer environmentally friendly, sustainable, facile separation, and high-performance MOF-based hydrogel photocatalysis platforms. The CuII-MOF 1 and CuI-MOF 2 were initially synthesized through a direct diffusion and single-crystal to single-crystal (SCSC) transformation method, respectively, and after the immobilization into alginate, more effective pollutant decontamination was achieved via the synergistic effect of the adsorption feature of hydrogel and in situ photodegradation of Cu-MOFs. Specifically, Cu-MOF-alginate composites present an improved and nearly completed Cr(VI) elimination at a short time of 15–25 min. Additionally, the congo red (CR) decolorization can be effectively enhanced in the presence of Cr(VI), and 1-alginate showed superior simultaneous decontamination efficiency of CR and Cr(VI) with 99% and 78%, respectively. Furthermore, Cu-MOF-alginate composites can maintain a high pollutant removal after over 10 continuous cycles (95% for Cr(VI) after 14 runs, and 90% for CR after 10 runs). Moreover, the Cr(VI)/CR degradation mechanism for Cu-MOF-alginate composite was investigated.
Shape control of nickel sulfide (NiS2) catalysts is beneficial for boosting their catalytic performances, which is vital to their practical application as a class of advanced non-noble electro-catalysts. However, precisely controlling the formation kinetics and fabricate ultrathin NiS2 nanostructures still remains challenge. Herein, we provide an injection rate-mediated method to fabricate ultrathin NiS2 nanocages (HNCs) with hierarchical walls, high-density lattice defects and abundant grain boundaries (GBs). Through mechanism analysis, we find the injection rate determines the concentration of S2− in the steady state and thus control the growth pattern, leading to the formation of NiS2 HNCs at slow etching kinetics and NiCo PBA@NiS2 frames at fast etching kinetics, respectively. Benefiting from the ultrathin and hierarchical walls that minimize the mass transport restrictions, the high-density lattice defects and GBs that offer abundant unsaturated reaction sites, the NiS2 HNCs exhibit obviously enhanced electrocatalytic activity and stability toward OER, with overpotential of 255 mV to reach 10 mA/cm2 and a Tafel slope of 27.44 mV/dec, surpassing the performances of NiCo PBA@NiS2 frames and commercial RuO2.
Industrial high-current-density oxygen evolution catalyst is the key to accelerating the practical application of hydrogen energy. Herein, Co9S8/CoS heterojunctions were rationally encapsulated in S, N-codoped carbon ((Co9S8/CoS)@SNC) microleaf arrays, which are rooted on S-doped carbonized wood fibers (SCWF). Benefiting from the synergistic electronic interactions on heterointerfaces and the accelerated mass transfer by array structure, the obtained self-supporting (Co9S8/CoS)@SNC/SCWF electrode exhibits superior performance toward alkaline oxygen evolution reaction (OER) with an ultra-low overpotential of 274 mV at 1000 mA/cm2, a small Tafel slope of 48.84 mV/dec, and ultralong stability up to 100 h. Theoretical calculations show that interfacing Co9S8 with CoS can upshift the d-band center of the Co atoms and strengthen the interactions with oxygen intermediates, thereby favoring OER performance. Furthermore, the (Co9S8/CoS)@SNC/SCWF electrode shows outstanding rechargeability and stable cycle life in aqueous Zn-air batteries with a peak power density of 201.3 mW/cm2, exceeding the commercial RuO2 and Pt/C hybrid catalysts. This work presents a promising strategy for the design of high-current-density OER electrocatalysts from sustainable wood fiber resources, thus promoting their practical applications in the field of electrochemical energy storage and conversion.
Mn-based P2-type oxides are considered as promising cathodes for Na-ion batteries; however, they face significant challenges, including structural degradation when charged at high cutoff voltages and structural changes upon storing in a humid atmosphere. In response to these issues, we have designed an oxide with co-doping of Cu and Al which can balance both cost and structural stability. The redox reaction of Cu2+/3+ can provide certain charge compensation, and the introduction of Al can further suppress the Jahn-Teller effect of Mn, thereby achieving superior long-term cycling performance. The ex-situ XRD testing indicates that Cu/Al co-doping can effectively suppress the phase transition of P2-O2 at high voltage, thereby explaining the improvement in electrochemical performance. DFT calculations reveal a high chemical tolerance to moisture, with lower adsorption energy for H2O compared to pure Na0.67Cu0.25Mn0.75O2. A representative Na0.67Cu0.20Al0.05Mn0.75O2 cathode demonstrates impressive reversible capacities of 148.7 mAh/g at 0.2 C, along with a remarkable capacity retention of 79.1% (2 C, 500 cycles).
Solid-state electrolytes (SSEs), as the core component within the next generation of key energy storage technologies - solid-state lithium batteries (SSLBs) - are significantly leading the development of future energy storage systems. Among the numerous types of SSEs, inorganic oxide garnet-structured superionic conductors Li7La3Zr2O12 (LLZO) crystallized with the cubic Ia3d space group have received considerable attention owing to their highly advantageous intrinsic properties encompassing reasonable lithium-ion conductivity, wide electrochemical voltage window, high shear modulus, and excellent chemical stability with electrodes. However, no SSEs possess all the properties necessary for SSLBs, thus both the ionic conductivity at room temperature and stability in ambient air regarding cubic garnet-based electrolytes are still subject to further improvement. Hence, this review comprehensively covers the nine key structural factors affecting the ion conductivity of garnet-based electrolytes comprising Li concentration, Li vacancy concentration, Li carrier concentration and mobility, Li occupancy at available sites, lattice constant, triangle bottleneck size, oxygen vacancy defects, and Li-O bonding interactions. Furthermore, the general illustration of structures and fundamental features being crucial to chemical stability is examined, including Li concentration, Li-site occupation behavior, and Li-O bonding interactions. Insights into the composition-structure-property relations among cubic garnet-based oxide ionic conductors from the perspective of their crystal structures, revealing the potential compatibility conflicts between ionic transportation and chemical stability resulting from Li-O bonding interactions. We believe that this review will lay the foundation for future reasonable structural design of oxide-based or even other types of superionic conductors, thus assisting in promoting the rapid development of alternative green and sustainable technologies.
Developing effective strategy for constructing the electrocatalysts enable tri-functional electrocatalytic activity of hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is the premise to achieve both the zinc-air battery (ZAB) and overall water splitting. Herein, we utilize density functional theory to calculate the cobalt nitride (CoxN, x = 1, 2, 4, 5.47) system, revealing that the Co5.47N maybe exhibits a tri-functional activity due to the diverse valence states and high-density d-electron state of Co site. Furthermore, the electron of Co site is further delocalized by the electronic compensation effect of vanadium nitride (VN), thus improving the intermediates absorption and electrocatalytic activity. Accordingly, the Co5.47N/VN heterojunction is designed and synthesized via an electrospinning and a subsequent pyrolysis route. As expected, it displays excellent HER, OER, and ORR activity in alkaline electrolyte, which can be applied to assemble ZAB with a high power density of 207 mW/cm2 and overall water splitting system only requires a lower voltage of 1.53 V to achieve 10 mA/cm2. The electron regulation effect of VN makes the Co valence state decrease in the reduction reaction whereas increase in the oxidization reaction as evidenced by quasi-operando XPS analyses. Importantly, two ZABs connected in series could drive overall water splitting, indicating the potential application in renewable energy technologies.