No abstract

Constructing heterojunction is an effective strategy to enhance photocatalytic performance of photocatalysts. Herein, we fabricated ZnTiO 3 /Bi 4 NbO 8 Cl heterojunction with improved performance via a typical mechanical mixing method. The rhodamine (RhB) degradation rate over heterojunction is higher than that of individual ZnTiO 3 or Bi 4 NbO 8 Cl under Xenon-arc lamp irradiation. Combining ZnTiO 3 with Bi 4 NbO 8 Cl can inhibit the recombination of photo-excited carriers. The improved quantum efficiency was demonstrated by transient-photocurrent responses (PC), electrochemical impedance spectroscopy (EIS), photoluminescence (PL) spectra, and time-resolved PL (TRPL) spectra. This research may be valuable for photocatalysts in the industrial application.

No abstract

Significantly maximizing the density of active sites while increasing the mass transfer rate of the catalyst is critical to increasing the activity toward oxygen reduction reaction (ORR). Herein, a Fe, Co, and N co-doped carbon catalyst in the form of hollow carbon nanocage grafted with carbon nanotubes (FeCo-HNC/CNT) was synthesized using a seed-mediated growth method with in situ doping strategy followed by one-step high-temperature pyrolysis without additional acid-etching or re-pyrolysis. Benefiting from the in situ doping of Fe3+ ions, the FeCo-HNC/CNT catalyst exhibited a relatively high content of active sites (M-N), unique concave hollow structure, hierarchical pore structure, and in situ growth of carbon nanotubes. The utilization of active sites and mass transport within the carbon matrix are promoted. Remarkably, the FeCo-HNC/CNT catalyst exhibits significantly high activity with the onset potential (E onset) of 1.060 V vs RHE and half-wave potential (E 1/2) of 0.902 V vs RHE in 0.1 M KOH solution. The stability is also enhanced with only 2.7 mV loss after 10,000 cycles of CV test. The ORR activity of the FeCo-HNC/CNT catalyst (E onset = 0.926 V vs RHE and E 1/2 = 0.817 V vs RHE) is comparable to that of commercial Pt/C catalysts in 0.5 M H2SO4 solution. This work provides a facile and effective method to prepare an efficient bimetal-doped M-N-C carbon-based ORR electrocatalyst with a proper hierarchical porous structure.