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In various ferroelectric-based photovoltaic materials after low-band-gap engineering, the process by which high-field polarization induces the depolarizing electric field (Edp) to accelerate the electron–hole pair separation in the visible light photocatalytic process is still a great challenge. Herein, a series of semiconducting KN-based ferroelectric catalytic materials with narrow multi-band gaps and high-field polarization capabilities are obtained through the Ba, Ni, and Bi co-doping strategy. Stable Edpcaused by high-field poling enhanced the visible photocatalytic hydrogen evolution in a 0.99KN–0.01BNB sample with a narrow band gap and optimal ferroelectricity, which can be 5.4 times higher than that of the unpoled sample. The enhanced photocatalytic hydrogen evolution rate can be attributed to the synergistic effect of the significant reduction of the band gap and the high-field-polarization-induced Edp. The change in the band position in the poled sample further reveals that high-field poling may accelerate the migration of carriers through band bending. Insights into the mechanism by which catalytic activity is enhanced through high-field-polarization-induced Edpmay pave the way for further development of ferroelectric-based catalytic materials in the photocatalytic field.

Mg3Sb2-based compounds by virtue of nontoxicity and low-cost have become a promising class of candidates for midtemperature thermoelectric power generation. Here, we successfully fabricated n-type Mg3Sb2-based materials using an inexpensive and efficient approach of one-step ball milling and spark plasma sintering, and demonstrate that a complementary and favorable effect of multiple elements coalloying/-doping leads to an excellent thermoelectric performance. The intrinsic p-type conducting behavior for Mg3Sb2could be changed to n-type through Bi and Se coalloying on Sb sublattices with excess Mg, resulting from the suppression of Mg vacancies and the formation of Mg interstitial. Furthermore, Mn doping on Mg sublattices could soften the chemical bonds, leading to the increase of carrier mobility and concentration simultaneously. Additionally, multielement coalloying/-doping could significantly increase the lattice disorder, which undoubtedly strengthens the phonon scattering and readily results in a suppressed lattice thermal conductivity. As a result, a highest ZTvalue of 1.6 at 723 K and an average ZTvalue up to 1.1 were obtained in the temperature range of 323–723 K in the Mg3.18Mn0.02Sb1.5Bi0.49Se0.01sample, which is one of the highest values among the Te free Mg3Sb2. This work could give guidance for improving the thermoelectric performance of Zintl phase materials or even others using the multielement codoping/-alloying strategy.

Antimony telluride (Sb2Te3) and its based alloys are of importance to p-type semiconductors for thermoelectric applications near room temperature. Herein, we report a simple, low-energy intensive, and scalable surfactant-assisted reflux method for the synthesis of Sb2Te3nanoparticles in the solvent ethylene glycol (EG) at low temperatures (120–180 °C). The formation mechanism of platelike Sb2Te3nanoparticles is proposed. Also, it is found that the size, shape, and chemical composition of the products could be controlled by the introduction of organic surfactants (CTAB, PVP, etc.) or inorganic salts (EDTA-Na2, NaOH, etc.). Additionally, the collected Sb2Te3nanoparticles were further fabricated into nanostructured pellets using cold-compaction and annealing techniques. Low resistivity [(7.37–19.4) × 10–6Ω m], moderate Seebeck coefficient (103–141 μV K–1), and high power factor (10–16 × 10–4W m–1K–2) have been achieved in our Sb2Te3-nanostructured bulk materials. The relatively low thermal conductivity (1.32–1.55 W m–1K–1) is attained in the nanobulk made of PVP-modified nanoparticles, and values of ZTin the range of 0.24–0.37 are realized at temperatures ranging from 50 to 200 °C. Our researches set forth a new avenue in promoting practical applications of Sb2Te3-based thermoelectric power generation or cooling devices.