Tetragonal tungsten bronzes (TTBs), an important class of oxides known to exhibit ferroelectricity, undergo complex distortions, including rotations of oxygen octahedra, which give rise to either incommensurately or commensurately modulated superstructures. Many TTBs display broad, frequency-dependent relaxor dielectric behavior rather than sharper frequency-independent normal ferroelectric anomalies, but the exact reasons that favor a particular type of dielectric response for a given composition remain unclear. In this contribution the influence of incommensurate/commensurate displacive modulations on the onset of relaxor/ferroelectric behavior in TTBs is assessed in the context of basic crystal-chemical factors, such as positional disorder, ionic radii and polarizabilities, and point defects. We present a predictive crystal-chemical model that rationalizes composition–structure–properties relations for a broad range of TTB systems.

increasing interest since it exhibits a suppressed Fenton reactivity in comparison to Fe-N-C while maintains a remarkable catalytic activity. [18-20] To rationally design CoN -C catalyst for ORR, downsizing active species to single-atom scale and intentionally incorporating specific N into carbon matrix have been proposed to facilitate the catalytic process. [21-27] The former strategy can achieve a maximum atom-utilization efficiency and full exposure of active sites while the latter strategy usually involves pyridinic-N construction to optimize the charge distribution and improve the density of states at the Fermi level of the adjacent C atoms, facilitating the oxygen adsorption and reduction reaction. [28,29] For example, Yin et al. synthesized singleatom CoN x-C electrocatalyst through the pyrolysis of cobalt-coordinated framework porphyrin with graphene and found that it exhibited a high half-wave potential of 0.83 V, much better than Co nanoparticles-N-C electrocatalyst (0.73 V). [30] Han et al. investigated the size effect on the electrocatalytic activity of Co catalysts from nanometer to singleatom scale, demonstrating that cobalt single atoms on N-doped carbon could achieve a higher half-wave potential (0.82 V) and a larger limiting diffusion current density (4.96 mA cm −2) than atomic Co clusters (0.81 V, 4.44 mA cm −2) and Co nanoparticles counterpart (0.80 V, 3.86 mA cm −2). [31] Wang et al. developed a laser irradiation strategy to modulate the relative contents of pyridinic and pyrrolic nitrogen dopants in the electrocatalyst and reported that pyridinic-NCo bonding instead of pyrrolic-N bonding could optimize the adsorption energy of reaction intermediates in ORR process. [32] Despite prominent achievements that have been made recently, most studies on CoN -C catalysts focused on only one of the above-proposed strategies, and thus their catalytic performance is still unsatisfied to meet the practical application. Therefore, developing an effective synthetic strategy for the integration of generating atomically dispersed active sites and achieving pyridinic-N-optimized electronic structure to increase the catalytic activity of CoN -C catalyst is highly demanded but remains significant challenging. Herein, we have innovatively developed a highly effective lysozyme (Lys)-assisted metal-organic framework (MOF) approach to prepare single-atom Co implanted pyridinic-N doped porous carbon catalysts. During the pyrolysis process, the attached Lys on the surrounding of Co-ZIF-8 (zeolitic imidazolate frameworks) not only can effectively trap metal atoms Engineering transition metal-nitrogen-carbon (TM-N-C) catalysts with highdensity accessible active sites and optimized electronic structure holds great promise in the context of the electrochemical oxygen reduction reaction (ORR). Herein, a novel modification of a lysozyme-modified zeolitic imidazolate framework with isolated Co atoms anchored on dominated pyridinic-N doped carbon (Co-pyridinic N-C) is reported. The atomically dispersed Co allows the maximum ...

Addressing the intrinsic charge transport limitation of metal oxides has been of significance for pursuing viable PEC water splitting photoelectrodes. Growing a photoelectrode with conductive nanoobjects embedded in the matrix is promising for enhanced charge transport but remains a challenge technically. We herein show a strategy of embedding laser generated nanocrystals in BiVO 4 photoanode matrix, which achieves photocurrent densities of up to 5.15 mA cm −2 at 1.23 V RHE (from original 4.01 mA cm −2 ) for a single photoanode configuration, and 6.22 mA cm −2 at 1.23 V RHE for a dual configuration. The enhanced performance by such embedding is found universal owing to the typical features of laser synthesis and processing of colloids (LSPC) for producing ligand free nanocrystals in desired solvents. This study provides an alternative to address the slow bulk charge transport that bothers most metal oxides, and thus is significant for boosting their PEC water splitting performance.

High-entropy materials (HEMs), including high-entropy alloys (HEAs), high-entropy oxides (HEOs), and other high-entropy compounds, have gained significant interests over the past years. These materials have unique structures with the coexistence of antisite disordering and crystal periodicity, which were originally investigated as structural materials. Recently, they have emerged for energyrelated applications, such as catalysis, energy storage, etc. In this work, we review the research progress of energy-related applications of HEMs. After an introduction on the background, theory, and syntheses of HEMs, we survey their applications including electrocatalysis, batteries, and others, aiming to retrieve the correlations between their structures and performances. In the end, we discussed the challenges and future directions for developing HEMs.

Pt-Cu alloy concave nanocubes enclosed by high-index {511} facets were synthesized in high yields and exhibited substantially enhanced electrocatalytic properties for methanol oxidation relative to commercial Pt/C.