Nitrogen-containing carbon enriched with tungsten atoms prepared by carbonization of polyaniline

Polyaniline (PANI) salts with tungstosilicic (TSA) and phosphotungstic acids (PTA) were prepared by reprotonation of PANI base. Partial protonation of the precursor base was confirmed by Raman spectroscopy and by conductivity measurements. Conductivity of polyaniline tungstosilicate (PANI-TSA) and polyaniline phosphotungstate (PANI-PTA) after reprotonation measured on compressed pellets was found to be 1 × 10–5 S cm−1 and 4 × 10–6 S cm−1, that is significantly higher compared to conductivity of PANI base (⁓ 10–11 S cm–1). According to thermogravimetric and elemental analyses, the amount of heteropolyacids in the resulting salts was ≈ 20 wt%, which corresponded to ≈ 15 wt% of tungsten. Tungsten- and nitrogen-containing carbon derivatives were obtained by carbonization of the prepared PANI salts without losing their conductivity (⁓10–7 S cm–1). Successful carbonization was confirmed by vibrational spectroscopy. Electron microscopy showed that globular morphology typical for PANI base was not affected by reprotonation and carbonization procedures. Elemental analysis confirmed 25.6 and 17.9 wt% of tungsten, 9.7 and 9.6 wt% of nitrogen in the carbonized PANI-PTA and PANI-TSA, respectively. The prepared carbon derivatives can be potentially useful for electrocatalysis.