1 research outputs found
Phosphorus-Doped Graphitic Carbon Nitride Nanotubes with Amino-rich Surface for Efficient CO<sub>2</sub> Capture, Enhanced Photocatalytic Activity, and Product Selectivity
Phosphorus-doped
graphitic carbon nitrides (P-g-C<sub>3</sub>N<sub>4</sub>) have recently
emerged as promising visible-light photocatalysts for both hydrogen
generation and clean environment applications because of fast charge
carrier transfer and increased light absorption. However, their photocatalytic
performances on CO<sub>2</sub> reduction have gained little attention.
In this work, phosphorus-doped g-C<sub>3</sub>N<sub>4</sub> nanotubes
are synthesized through the one-step thermal reaction of melamine
and sodium hypophosphite monohydrate (NaH<sub>2</sub>PO<sub>2</sub>·H<sub>2</sub>O). The phosphine gas generated from the thermal
decomposition of NaH<sub>2</sub>PO<sub>2</sub>·H<sub>2</sub>O
induces the formation of P-g-C<sub>3</sub>N<sub>4</sub> nanotubes
from g-C<sub>3</sub>N<sub>4</sub> nanosheets, leads to an enlarged
BET surface area and a unique mesoporous structure, and creates an
amino-rich surface. The interstitial doping phosphorus also down shifts
the conduction and valence band positions and narrows the band gap
of g-C<sub>3</sub>N<sub>4</sub>. The photocatalytic activities are
dramatically enhanced in the reduction both of CO<sub>2</sub> to produce
CO and CH<sub>4</sub> and of water to produce H<sub>2</sub> because
of the efficient suppression of the recombination of electrons and
holes. The CO<sub>2</sub> adsorption capacity is improved to 3.14
times, and the production of CO and CH<sub>4</sub> from CO<sub>2</sub> increases to 3.10 and 13.92 times that on g-C<sub>3</sub>N<sub>4</sub>, respectively. The total evolution ratio of CO/CH<sub>4</sub> dramatically
decreases to 1.30 from 6.02 for g-C<sub>3</sub>N<sub>4</sub>, indicating
a higher selectivity of CH<sub>4</sub> product on P-g-C<sub>3</sub>N<sub>4</sub>, which is likely ascribed to the unique nanotubes structure
and amino-rich surface