Heat map of log10-transformed proportion of <i>arsC</i>-like and <i>arrA</i>-like (a), <i>aioA</i>-like (b) and <i>arsM</i>-like (c) genes distributed in five metagenomic datasets.

<p>Phylogenetic analysis used full-length proteins derived from each subdatabase. Complete linkage clustering of five samples was calculated based on the composition and relative abundance of arsenite methylation, arsenite oxidation and arsenate reduction genes. Scales of completely black (−4), pale (−4 to −3), yellow (−3 to −2), orange (−2 to −1), and red(>−1) indicated the abundance of 0%, 0.01–0.1%, 0.1–1%, 1–10%, and >10%, respectively.</p

Hierarchical Nanotubular Anatase/Rutile/TiO₂(B) Heterophase Junction with Oxygen Vacancies for Enhanced Photocatalytic H₂ Production

Oxygen vacancies have been demonstrated to enhance the interfacial charge separation in TiO₂-based photocatalysts. In this report, we explored a facile route to synthesize hierarchical nanotubular anatase/rutile/TiO₂(B) nanostructures with high surface area and defective electronic structure. The formation of oxygen vacancies in the heterophase junction was analyzed by UV–vis absorption spectra, electron spin resonance, and X-ray photoelectron spectroscopy. The enhanced interfacial charge separation and transportation ensured the excellent photoactivity of oxygen-deficient junctions for the photocatalytic production of hydrogen. As a result, the defective anatase/rutile/TiO₂(B) junction showed a high hydrogen evolution rate of 2.79 mmol/h, which was 19 times higher than blank TiO₂ nanotubes. The results demonstrate that defect modulation is a powerful tool to enhance the catalytic performances of TiO₂-based photocatalysts

Tungsten-Assisted Phase Tuning of Molybdenum Carbide for Efficient Electrocatalytic Hydrogen Evolution

Phase tuning during crystal phase transformation is an important but challenging step toward the development of effective hydrogen evolution reaction (HER) catalysts. Herein, we report on a feasible approach to achieve effective polycrystalline molybdenum carbides during transformation from α-phase to β-phase through the regulation of additive (tungsten) amount. Benefiting from the optimal Mo–C bond lengths and abundant active sites, molybdenum carbide prepared with a moderate addition of tungsten enhanced electrocatalytic activity and stability compared with pure α-phase and β-phase Mo₂C in the HER, and only required an overpotential of 148 and 93 mV to drive 20 mA cm^–2 of current density in 0.5 M H₂SO₄ and 1.0 M KOH, respectively

Chemical composition analysis of the soil samples were based on (a) FT-IR, (b) XPS.

<p>Chemical composition analysis of the soil samples were based on (a) FT-IR, (b) XPS.</p

The relationships between the abundance of functional proteins and arsenic concentration across the 5 sites, with x axis showing abundance of functional proteins ((a) indicate <i>arsC</i> and (b) indicate <i>aioA</i>), y axis showing arsenic concentration.

<p>Points are arranged according to the local concentration of arsenic (from low concentration to high concentration, which from 34.1 mg L⁻¹ to 821.2 mg L⁻¹) corresponding with the abundance of functional proteins</p

Chemical composition analysis of the sand filter based on (a) Fourier transform infrared (FT-IR) (b) X-ray photoelectron spectroscopy (XPS).

<p>Chemical composition analysis of the sand filter based on (a) Fourier transform infrared (FT-IR) (b) X-ray photoelectron spectroscopy (XPS).</p

Relative abundance of nitrification- and denitrification-related gene sequences retrieved from two metagenomic datasets.

<p>Values are normalized by randomly sampling 100,000 assembled sequences per sample.</p

Vertical distribution of 16S rRNA (bacteria and archaea), <i>amoA</i>(bacteria and archaea), and <i>nosZ</i> gene in the sand filter system of the drinking water treatment facility.

<p>The results were obtained from real-time PCR assay. Error bars represent standard deviation from three independent experiments.</p

Phylogenetic trees based on the (a) archaeal 16S rRNA and (b) archaeal <i>amoA</i> representative sequences (OTUs, 97% similarity) from the DZhigh sample.

<p>The numbers on the branch nodes represent percentage of bootstrap resamplings based on 1000 replicates (only ≥50% are shown). The scale bar indicates the number of nucleotide substitutions per site. The relative abundance of each OTU in each clone library is shown in parentheses.</p

Taxonomic classification of microbial communities in the soil samples at (a) domain level and (b) phylum level.

<p>All the information was obtained from metagenomic datasets revealed by Illumina.</p