TY - JOUR

T1 - Photocatalytic H2 Production from Naphthalene by Various TiO2 Photocatalysts

T2 - Impact of Pt Loading and Formation of Intermediates

AU - Al-Madanat, Osama

AU - AlSalka, Yamen

AU - Dillert, Ralf

AU - Bahnemann, Detlef W.

N1 - Funding Information: Acknowledgments: Financial support from the Katholischer Akademischer Ausländer-Dienst (KAAD) and Graduiertenakademie at Gottfried Wilhelm Leibniz Universität Hannover are gratefully acknowledged for providing scholarships for Osama Al-Madanat to perform his O. Al-Madanat wishes to thank Mariano Curti for the helpful assistance and discussion while preparing the manuscript. The publication of this article was funded by the Open Access Publishing Fund of Leibniz Universität Hannover. Financial support from the Global Research Laboratory Program (2014 K1 A1 A2041044), Korea Government (MSIP) through NFR is gratefully acknowledged.

PY - 2021/1/13

Y1 - 2021/1/13

N2 - This work presents a comparative study of the efficiency of two commercial TiO 2 photocat-alysts, Aeroxide P25 (ATiO 2) and Sachtleben Hombikat UV100 (HTiO 2 ), in H 2 production from an aqueous solution of naphthalene. The TiO 2 photocatalysts were platinized by the photodeposition method varying the platinum content of the suspension to 0.5, 1.0, and 5.0 wt%. A full physico-chemical characterization for these materials was performed, showing no structural effects from the deposition method, and confirming a well dispersion of nanosized-Pt 0 particles on the surface of both photocatalysts. Pristine ATiO 2 shows around 14% higher photocatalytic fractional conversion of naphthalene than pristine HTiO 2 after 240 min of irradiation, while both materials exhibit negligible activity for H 2 formation. The 0.5 wt% Pt-HTiO 2 increases the photocatalytic fractional conversion of naphthalene from 71% to 82% and produces 6 µmol of H 2 . However, using a higher Pt content than the optimal platinization ratio of 0.5 wt% dramatically inhibits both processes. On the other hand, regardless of the fractional ratio of Pt, the platinization of ATiO 2 results in a decrease in the fractional conversion of naphthalene by 4% to 33% of the pristine value. Although the presence of Pt islands on the surface of the ATiO 2 is essential for the H 2 evolution, no dependency between the Pt ratio and the H 2 formation rate was observed since all the platinized materials show a similar H 2 formation of around 3 µmol. Based on the EPR results, the higher photocatalytic activity of the Pt-HTiO 2 is attributed to the efficient charge carrier separation and its larger surface area. The recyclability test confirms that the inhibition of the photocatalytic process is related to the deactivation of the photocatalyst surface by the adsorption of the photoformed intermediates. A strong relationship between the photocatalytic activity and the kind of the aromatic compounds was observed. The H 2 evolution and the photooxidation of the aromatic hydrocarbons exhibit higher photonic efficiencies than that of their corresponding hydroxylated compounds over the Pt-HTiO 2 .

AB - This work presents a comparative study of the efficiency of two commercial TiO 2 photocat-alysts, Aeroxide P25 (ATiO 2) and Sachtleben Hombikat UV100 (HTiO 2 ), in H 2 production from an aqueous solution of naphthalene. The TiO 2 photocatalysts were platinized by the photodeposition method varying the platinum content of the suspension to 0.5, 1.0, and 5.0 wt%. A full physico-chemical characterization for these materials was performed, showing no structural effects from the deposition method, and confirming a well dispersion of nanosized-Pt 0 particles on the surface of both photocatalysts. Pristine ATiO 2 shows around 14% higher photocatalytic fractional conversion of naphthalene than pristine HTiO 2 after 240 min of irradiation, while both materials exhibit negligible activity for H 2 formation. The 0.5 wt% Pt-HTiO 2 increases the photocatalytic fractional conversion of naphthalene from 71% to 82% and produces 6 µmol of H 2 . However, using a higher Pt content than the optimal platinization ratio of 0.5 wt% dramatically inhibits both processes. On the other hand, regardless of the fractional ratio of Pt, the platinization of ATiO 2 results in a decrease in the fractional conversion of naphthalene by 4% to 33% of the pristine value. Although the presence of Pt islands on the surface of the ATiO 2 is essential for the H 2 evolution, no dependency between the Pt ratio and the H 2 formation rate was observed since all the platinized materials show a similar H 2 formation of around 3 µmol. Based on the EPR results, the higher photocatalytic activity of the Pt-HTiO 2 is attributed to the efficient charge carrier separation and its larger surface area. The recyclability test confirms that the inhibition of the photocatalytic process is related to the deactivation of the photocatalyst surface by the adsorption of the photoformed intermediates. A strong relationship between the photocatalytic activity and the kind of the aromatic compounds was observed. The H 2 evolution and the photooxidation of the aromatic hydrocarbons exhibit higher photonic efficiencies than that of their corresponding hydroxylated compounds over the Pt-HTiO 2 .

KW - Aeroxide P25

KW - Charge carrier

KW - EPR

KW - H production

KW - Hombikat UV100

KW - Naphthalene

KW - Photoreforming

KW - Pt-TiO

UR - http://www.scopus.com/inward/record.url?scp=85100181235&partnerID=8YFLogxK

U2 - 10.3390/catal11010107

DO - 10.3390/catal11010107

M3 - Article

VL - 11

JO - CATALYSTS

JF - CATALYSTS

SN - 2073-4344

IS - 1

M1 - 107

ER -