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Solid oxide electrolysis cells (SOECs) show significant promise in converting CO2to valuable fuels and chemicals, yet exploiting efficient electrode materials poses a great challenge. Perovskite oxides, known for their stability as SOEC electrodes, require improvements in electrocatalytic activity and conductivity. Herein, vanadium(V) cation is newly introduced into the B-site of Sr2Fe1.5Mo0.5O6-δperovskite to promote its electrochemical performance. The substitution of variable valence V5+for Mo6+along with the creation of oxygen vacancies contribute to improved electronic conductivity and enhanced electrocatalytic activity for CO2reduction. Notably, the Sr2Fe1.5Mo0.4V0.1O6-δbased symmetrical SOEC achieves a current density of 1.56 A cm–2at 1.5 V and 800 °C, maintaining outstanding durability over 300 h. Theoretical analysis unveils that V-doping facilitates the formation of oxygen vacancies, resulting in high intrinsic electrocatalytic activity for CO2reduction. These findings present a viable and facile strategy for advancing electrocatalysts in CO2conversion technologies.

Traditional catalysts are usually synthesized by sputtering, electrochemical deposition, or hydrothermal methods, and they also need to be combined with substrates to obtain the working electrodes. Here we introduce a new route to produce an efficient catalyst for oxygen evolution reaction (OER) that is made by ball milling and sintering. By using Se as a grinding aid, the bulk electrode Ni1–xFexSe1.15is obtained with high porosity and robust mechanical strength after sintering. Active Ni1–xFexlayered double hydroxide (LDH) nanosheets are subsequently produced on the surface of the Ni1–xFexSe1.15by in situelectrochemical oxidation. Compared with traditional synthesis methods, the new process displays superior advantages, such as producing an electrode that is substrate-free and exhibits robust mechanical strength as well as being cost-effective for mass production. Additionally, V- and Mn-doped Ni0.75Fe0.25-LDH exhibit comparable and competent OER performance in 1 M KOH solution. Ni0.71V0.04Fe0.25-LDH achieves current densities of 100 and 1000 mA cm–2at overpotentials of 244 and 300 mV, respectively. This work demonstrates a promising way to synthesize highly efficient and robust electrocatalysts for water oxidation.

The perovskite solar cells (PSCs) based on cesium lead bromide (CsPbBr3) with outstanding environmental stability and low preparation cost are regarded as one of the most promising photovoltaic devices for commercial applications. However, the performance of CsPbBr3PSCs can be badly deteriorated by the intense charge recombination arising from the ionic defects at the grain boundaries of perovskite film. To cope with this issue, we adopt an amino acid of l-lysine with two amino and one carboxyl groups as a chemical additive to incorporate into perovskite film to simultaneously anchor the uncoordinated Pb2+(Cs+) and halogen ion defects. Further, the grain size of CsPbBr3perovskite is boosted from 688 to over 1000 nm after l-lysine incorporation as a result of the decreased nucleation rate and the sufficient growth of perovskite, which effectively reduce the grain boundaries for load defects. As expected, the optimized device achieves a best power conversion efficiency of 9.69% attributed to the remarkably reduced charge recombination and enhanced charge extraction arising from the efficient defects dual-passivation and enlarged grain size of perovskite film as well as the improved energy level alignment at the device interface after the introduction of l-lysine, which is elevated by 61.23% in comparison to 6.01% efficiency of the pristine one. Moreover, the unencapsulated device with l-lysine incorporation exhibits remarkable long-term stability in air with 80% RH at 25 °C and 0% RH at 80 °C as well as under continuous illumination conditions. This work provides an effective multifunctional additive for imperfection passivation and grain size enlargement of perovskite to build PSCs with high efficiency and stability.

The defect passivation of perovskite films is an efficacious way to further boost the power conversion efficiency (PCE) and long-term stability of perovskite solar cells (PSCs). In this work, ionic liquids (ILs) of 1-butyl-2,3-dimethylimidazolium chloride ([BMMIm]Cl) are used as a modification layer in perovskite films in carbon-based CsPbBr3PSCs without a hole-transporting material (HTM) for passivating the surface defects. The preliminary results demonstrate that the [BMMIm]Cl modifier passivates the surface defects of the perovskite film and reduces the valence band of perovskite close to the work function of the carbon electrode, which causes a remarkably inhibited nonradiative and radiative charge recombination, improved energy-level matching, and decreased energy loss. After optimization, a champion efficiency of 9.92% with a Vocas high as 1.61 V is achieved for the [BMMIm]Cl tailored carbon-based CsPbBr3PSC without HTM, which is improved by 61.3% in comparison with 6.15% for the control device. Furthermore, the encapsulation-free PSC presents good long-term stability after storage in an air atmosphere with 70% RH at 20 °C or 0% RH at 80 °C as well as under continuous illumination conditions for 30 days. The significantly improved PCE and stability in high humidity or temperature suggest that the perovskite passivation by ILs is an effective strategy for fabricating high-PCE and stable PSCs.

Metallopolymer nanowalls were prepared through a simple wet-chemical process using reduced graphene oxides as heterogeneous nucleation aids, which also help to form conductive electron paths. The nanowalls grow vertically on graphene surface with 100 -200 nm in widths and ∼20 nm in thickness. The Fe-based metallopolymer nanowall-based electrode shows best performance as O2cathode exhibiting high round-trip efficiencies and stable cycling performance among other transition metal containing metallopolymer counterparts. The electrode delivers discharge–charge capacities of 1000 mAh/g for 40 cycles and maintains round-trip efficiencies >78 % at 50 mA/g. The 1st-cycle round-trip efficiencies are 79%, 72%, and 65% at current densities of 50, 200, and 400 mA/g, respectively. The NMR analysis of the Fe-based metallopolymer based electrode after 40 cycles reveals slow formation of the side products, CH3CO2Li and HCO2Li.

Ultrathin 2D nanostructures have shown many unique properties and are attractive for various potential applications. Here, we demonstrated a strategy to synthesize ultrathin VOxnanosheets. The as-obtained ultrathin VOxnanosheets showed a large Brunauer–Emmett–Teller (BET) surface area of 136.3 m2g–1, which is much larger than that of 1D multilayer VOxnanotubes. As a proof of concept, these hydrophilic ultrathin nanosheets were applied in water treatment and exhibited excellent absorption capability to remove Rhodamine B (RhB) in wastewater owing to their large specific surface area, good hydrophilic property, and more negative zeta potential. In addition, this method could be generalized to prepare other 2D nanostructures with great potential for various attractive applications.