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The rising CO2 concentration in the atmosphere due to extensive use of fossil fuels has led to serious climate and environmental issues. One efficient solution is that CO2 capture from industrial emissions followed its conversion into value-added chemicals driven by renewable energies. CO2 electroreduction (CO2RR) features a green and sustainable fashion towards effective CO2 conversion, but still suffers from low multi-carbon selectivity and yield. Considering the pivotal role of CO intermediate in C–C coupling to multi-carbon formation, tandem CO2RR systems with separated CO generation and consumption components could facilitate the coupling between *CO-based intermediates to energy-intensive multi-carbons by manipulating CO diffusion and surface coverage. In this aspect, we comprehensively reviewed the design principles of tandem systems for CO2 electroreduction reaction. The chemistry behind the C–C coupling regarding to their distribution and diffusion was initially introduced, which was followed by achievements on tandem architectures, from catalysts, electrodes to systems. Future directions and perspectives on advanced tandem system designs for CO2RR were discussed at the end. This review contributes to the understanding of structure-performance correlations in tandem catalysis and helps guide the effective collection of multi-carbons of high-yield and high-selectivity. [ABSTRACT FROM AUTHOR]

The 0.55Bi(Mg1/2Ti1/2)O3–0.45PbTiO3 ceramics exhibit notable dielectric anomalies across three temperature ranges. The low‐temperature anomaly is attributed to a reentrant dipole glass‐like relaxor behavior; the mid‐temperature anomaly results from a ferro‐paraelectric phase transition; and the high‐temperature anomaly is associated with a diffuse phase transition. The system demonstrates favorable piezoelectric, electromechanical, and ferroelectric properties. Specifically, the ceramic presents a piezoelectric coefficient (d33) of 220 pC/N, an electromechanical coupling factor (kp) of 27%, and a remanant polarization (Pr) of 32.5 μC/cm2. Moreover, it maintains an operational capability up to 643 K. The unsaturated P(E) loops are formed through the coupling polarization between polar nanoregions (PNRs) and P4mm ferroelectric domains. By examining the electrical modulus, the dynamic PNRs resulting from ferroelectric phonon localization and the formation of P4mm ferroelectric domains were analyzed. The result reveals a mesoscale coupling relationship between the origin of high‐temperature piezoelectric stability and the dynamics of PNRs, thereby providing noble insights into the (1 − x)BiMeO3–xPbTiO3 system. [ABSTRACT FROM AUTHOR]

The 0.55Bi(Mg1/2Ti1/2)O3–0.45PbTiO3 ceramics exhibit notable dielectric anomalies across three temperature ranges. The low‐temperature anomaly is attributed to a reentrant dipole glass‐like relaxor behavior; the mid‐temperature anomaly results from a ferro‐paraelectric phase transition; and the high‐temperature anomaly is associated with a diffuse phase transition. The system demonstrates favorable piezoelectric, electromechanical, and ferroelectric properties. Specifically, the ceramic presents a piezoelectric coefficient (d33) of 220 pC/N, an electromechanical coupling factor (kp) of 27%, and a remanant polarization (Pr) of 32.5 μC/cm2. Moreover, it maintains an operational capability up to 643 K. The unsaturated P(E) loops are formed through the coupling polarization between polar nanoregions (PNRs) and P4mm ferroelectric domains. By examining the electrical modulus, the dynamic PNRs resulting from ferroelectric phonon localization and the formation of P4mm ferroelectric domains were analyzed. The result reveals a mesoscale coupling relationship between the origin of high‐temperature piezoelectric stability and the dynamics of PNRs, thereby providing noble insights into the (1 − x)BiMeO3–xPbTiO3 system. [ABSTRACT FROM AUTHOR]

Renewable energy driven electrochemical carbon dioxide reduction (CO2RR) to alcohols provides an effective pathway for achieving carbon neutrality and sustainable development. However, it is challenging to convert CO2 into ethanol due to the sluggish C−C coupling and complex 12 electron/proton transferred process, which has been achieved mainly on Cu catalysts but with poor selectivity. Herein, In2O3 catalysts were doped with small amount of Pd and exhibited high activity for CO2RR to ethanol with a high Faradaic efficiency (50.7 %) at low overpotential. The introduction of Pd promotes the transformation of reaction products from formic acid to ethanol by modulating the binding strength of *CO intermediates. The in‐situ ATR‐SEIRAS and DFT calculations proved that the formation of Pd−O−In could modulate the binding strength of *CO and enhanced its coverage, thus facilitating C−C coupling step towards ethanol. This study may provide a new strategy to the generation of high value‐added products from CO2 over Non‐Cu‐based catalysts. [ABSTRACT FROM AUTHOR]

Recent progresses have highlighted the enormous potentials of renewable electricities driven carbon dioxide (CO2) electrolysis in achieving carbon neutrality. However, its further industrial application is limited by low liquid product concentrations, which requires energy‐intensive downstream separation processing. Herein we report a CO2 and methanol co‐electrolysis strategy to produce formate at both electrodes and collect highly concentrated formate in zero‐gap CO2 electrolyzers. An anion exchange membrane was employed to enable formate product crossover from cathode to anode. A bismuth silicate derived nanofiber electrocatalyst with rich grain boundaries was synthesized and exhibited excellent formate selectivity (Faradaic efficiency >95%), high activity (partial current density >500 mA cm−2), as well as good stability (>120 h). Coupled with NiOX anode catalyst for methanol selective oxidation to formate in a zero‐gap electrolyzer, we demonstrate a ~180% of formate Faradaic efficiency and a full‐cell voltage of 2.43 V at an industrially relevant current density of 0.2 A cm−2. By decoupling product generation and collection, our electrolyzer produced a highly concentrated formate of 3.24 M, which could be directly used as anode fuel for fuel cells. [ABSTRACT FROM AUTHOR]

The Sr1-3x/2DyxTiO3 (x = 0.005, 0.01, 0.015, 0.02, 0.04, 0.06) ceramics are prepared sintered in N2 / air through a solid-state synthesis method. The effects of Dy doping amount and sintering process on the structure and dielectric properties of Sr1-3x/2DyxTiO3 ceramics were systematically investigated. We identify a novel Sr1-3x/2DyxTiO3 ceramic system sintered in N2 that exhibits the most superior dielectric performance when x = 0.01. At room temperature, the εr and tanδ of Sr0.985Dy0.01TiO3 ceramic sintered in N2 are 29,000 and 0.07 at a frequency of 1 kHz, and 27,000 and 0.01 at a frequency of 10 kHz, respectively. Additionally, the εr of Sr0.985Dy0.01TiO3 ceramics sintered in N2 has an excellent temperature stability at high temperatures, with a change rate within the range of ± 15% at a frequency of 10 kHz ranging from 30 to 480 ℃. Through comparing Sr0.985Dy0.01TiO3 ceramic sintered in air, sintering in N2 significantly improved its εr and thermal stability. This study demonstrates that the improvement of processing techniques and doping strategies have enhanced the dielectric properties of the ceramics. [ABSTRACT FROM AUTHOR]

Electrosynthesis of value-added chemicals, directly from CO2, could foster achievement of carbon neutral through an alternative electrical approach to the energy-intensive thermochemical industry for carbon utilization. Progress in this area, based on electrogeneration of multicarbon products through CO2 electroreduction, however, lags far behind that for C1 products. Reaction routes are complicated and kinetics are slow with scale up to the high levels required for commercialization, posing significant problems. In this review, we identify and summarize state-of-art progress in multicarbon synthesis with a multiscale perspective and discuss current hurdles to be resolved for multicarbon generation from CO2 reduction including atomistic mechanisms, nanoscale electrocatalysts, microscale electrodes, and macroscale electrolyzers with guidelines for future research. The review ends with a cross-scale perspective that links discrepancies between different approaches with extensions to performance and stability issues that arise from extensions to an industrial environment. [ABSTRACT FROM AUTHOR]

0.6Bi(Mg0.5Ti0.5)O3–0.4Ba0.8Ca0.2(Ti0.875Zr0.125)O3 (0.6BMT–0.4BCZT) ceramics exhibit an ultrahigh dielectric thermal stability. In this work, the relationship between the local structure and the physical properties of this system is revealed using in situ XRD, in situ Raman, TEM and dielectric responses. It is found that the formation and freezing of both polar nanoregions (PNRs) and nanomosaic structures (NMSs) that comprise ferroelectrically active Ba/Ti rich and weakly polar Bi (and Mg) rich phases are responsible for the high dielectric thermal stability. Three dielectric anomalies, i.e. low-temperature re-entrant dipole-glass-like relaxor behavior, mid-temperature diffuse phase transition (DPT), and high-temperature local phase transitions can be described using the phenomenological statistical model. Furthermore, the relaxor behavior follows the Vogel–Fulcher law and the new glass model. The dipole-glass-like relaxor nature of 0.6BMT–0.4BCZT was characterized by P–E loops. The beta value obtained from the isothermal electrical modulus shows three critical temperatures corresponding to the formations of PNRs, NMS and local phase transition of calcium-containing perovskites. [ABSTRACT FROM AUTHOR]

(1 − x)K0.5Na0.5NbO3–xLa(Zn0.5Zr0.5)O3 [(1 − x)KNN–xLZZ, x = 0.005, 0.010, 0.015, 0.020] ceramics were synthesized to fulfill the application requirement of high-temperature ceramic capacitors. The influence of LZZ content on the phase structure, microstructure morphology, dielectric and conductivity behaviors of this system was conducted. An orthorhombic phase for 0.005 ≤ x ≤ 0.010 and an orthorhombic-tetragonal coexisting phase for 0.015 ≤ x ≤ 0.020 were determined by the X-ray diffraction, Rietveld refinement, and dielectric spectra. The ceramic with x = 0.015 exhibits an ultrahigh and stable permittivity (ε' ~ 1892, ± 15% variation) and a low dielectric loss (tanδ ≤ 0.05) in a wide temperature region of 82–382 °C owing to the composition heterogeneity-induced shoulder-like peak and diffuse phase transition from tetragonal to cubic. The activation energies from the high-temperature dielectric relaxation and conductivity behaviors initially enhance greatly and then increase slowly, which could be related to the synergy effect of decreased oxygen vacancies and microstructure morphology evolution. [ABSTRACT FROM AUTHOR]

Lead-free high-temperature piezoelectric ceramics of 1 mol% Mn-doped (0.75 − x)BiFeO3–0.25BaTiO3–xBi0.5K0.5TiO3 were prepared via a conventional solid-state sintering technique. The relationship between the phase structure and the electrical properties of this system was disclosed. A composition-induced structural transformation from rhombohedral to tetragonal was induced by increasing the BKT concentration. A morphotropic phase boundary (MPB) was formed at x = 0.010–0.015, which was confirmed by the Rietveld refinement and Raman spectroscopy deconvolution. In particular, the ceramic with x = 0.010 exhibits excellent performances with d33 = 149 pC N−1, kp = 38%, Pr = 28.2 μC cm−2 and TC = 615 °C. The high-temperature piezoelectricity of the sample with the MPB (x = 0.010) was characterized by in situ Raman spectroscopy and in situ d33 testing. The outstanding thermal stability of the crystal structure and the high depolarization temperature (Td ∼ 570 °C) indicate that the BF–BT–BKT system is a promising candidate for lead-free high-temperature piezoelectric sensing. [ABSTRACT FROM AUTHOR]

A monolithic supercapacitor electrode of a KNi0.67Co0.33PO4·H2O-graphene composite hydrogel supported on Ni foam (KNCP-GH/NF) is first prepared by a one-step hydrothermal method, which achieves notable improvements in the electrode surface area and mass-loading of active materials. The KNCP-GH/NF electrode enjoys a hierarchical open-porous structure, where the KNCP-GH composite hydrogel fills in the voids in NF and the porous graphene hydrogel (GH) simultaneously provides a large support surface for growing active KNCP nanoflowers. Accordingly, the KNCP-GH/NF electrode exhibits a strikingly high capacity of 3240 mC cm−2 (876 C g−1) at 2 mA cm−2 and a satisfactory rate performance with 78.3% retention at 100 mA cm−2. Further, an all-solid-state asymmetric supercapacitor, constituted by using KNCP-GH/NF and Fe2P/GH/NF as the cathode and anode, respectively, and PVA-KOH as the solid-state gel electrolyte, delivers a high energy density of 69.2 W h kg−1 (3.9 mW h cm−3) and a power density of 13 229 W kg−1 (720 mW h cm−3) as well as notable cyclability with 81.2% capacity retention after 10 000 charge/discharge cycles. These attractive performances suggest a promising potential for a hierarchically structured KNCP-GH/NF electrode for the high-performance energy storage application. [ABSTRACT FROM AUTHOR]

(1–x)K0.5Na0.5NbO3-xLaBiO3 [(1–x)KNN-xLB, x = 0, 0.005, 0.015] lead-free ceramics were prepared via a solid-state reaction route. An orthorhombic symmetry was determined for all samples by the Rietveld refinement of XRD patterns. The 0.995KNN-0.005LB ceramic (KNN-5LB) exhibits an ultrahigh and stable relative permittivity (ε' ~ 2158 ± 15%) with a low dielectric loss tangent (tanδ ≤ 3%) in a very broad operation temperature range from 172 °C to 450 °C due to two close diffuse phase transitions at ~200 °C and ~ 380 °C induced by La and an additional polarization from off-centered Bi ions. The Cole-Cole plot of iso-thermal complex impedance suggests that the high-temperature dielectric response of the KNN-5LB is attributed to the polarizations from grains, grain boundaries and electrode interfaces. Both the imaginary parts of impedance and modulus exhibit the thermally activated process and scaling behavior. The frequency dependent conductivity (σac) of the KNN-5LB follows the Universal Dielectric Response (UDR) law. The conduction mechanism is related to the small polaron hopping. [ABSTRACT FROM AUTHOR]

Battery-type materials (e.g., transition metal phosphates) have been intensely explored in supercapacitors due to their rich electroactive sites and high theoretical capacity. Yet poor rate performance, resulting in a low energy density at high current density, limits their further applications. Herein, an improvement in rate performance resulting from enhanced surface capacitive behaviour contribution has been observed in a hierarchically structured Co3(PO4)2/Ni–Co–O@Ni foam (CPNO-12). The optimized CPNO-12 synthesized through a facile hydrothermal treatment also exhibits a striking gravimetric and areal capacity of 1410C g−1 (14 100 mC cm−2) at 5 mA cm−2 and superb cyclability (91% of retention at 50 mA cm−2 after 12 000 cycles), which can be attributed to its unique hierarchical porous structure and high mass loading per area. More importantly, a high-performance all-solid-state asymmetric supercapacitor with CPNO-12 and Fe2P/graphene hydrogel@Ni foam as positive and negative electrodes respectively has been assembled; the device delivering a maximum energy density of 95 W h kg−1 (32 mW h cm−3) and maximum power density of 4000 W kg−1 (800 mW cm−3) has the potential to power sophisticated systems. These attractive performances confirm that an enhancement of capacitive behaviour in battery-type materials holds the promise for fabricating high-performance supercapacitors. [ABSTRACT FROM AUTHOR]