Porous boron nitride for combined CO₂ capture and photoreduction

Abstract

Moving from hexagonal boron nitride (h-BN), a well-known crystalline insulator, to amorphous BN, leads to the creation of a semiconductor able to photoreduce CO2 in the gas/solid phase, under UV-vis and pure visible light.

Boron Oxynitride Quantum Dots for CO2 Photoreduction

“…33 We attribute the weaker band at ~1000 cm -1 to B-O bonds arising from interior substituted oxygen atoms. 28,29 A broad O-H peak at ~3200 cm -1 is observed, highlighting edge hydroxide functionalisation and termination of the BNO QDs. 34,35 The bands at ~930 cm -1 and ~1200 cm -1 likely correspond to C-H and C-N/C-O bonds, respectively.…”

“…18,35,37 Compared to hydro-/solvothermal routes, bottom-up pyrolytic syntheses of BN, more so under the presence of ammonia 38 , aid the removal of carbon from the end product. 27,28 To gain further insight into the relative atomic surface composition and chemical states of the elements, we collected high resolution core level B 1s, C 1s, N 1s and O 1s spectra through XPS. In addition to B (39 at.%), a significant proportion of oxygen atoms (~50 at.…”

“…We consider BNO QDs as direct band-gap semiconductors based on literature. 40 We followed the same methodology as in a previous study 28 to determine the band structure of the BNO QDs by measuring the valence band offset (ΔEVB) and work function (Φ) through XPS measurements (Fig. S2).…”

“…Hence, the work function (Φ) and valence band offset (ΔEVB) take negative values relative to absolute vacuum based on the notation outlined in our previous study. 28 The BNO QDs exhibited a valence band offset of -3.10 eV and a work function of -3.90 eV (Fig. S2).…”

“…S4. After the completion of the reaction, the mass spectra shows dominant peaks of m/z = 45 ( 13 CO2) and m/z = 29 ( 13 CO) with no peak for 12 CO (m/z = 28) observed. Corresponding to this, a 13 CO peak (m/z = 29) observed in the gas chromatogram.…”