Journal of Photochemistry & Photobiology, A: Chemistry xxx (xxxx) xxx Please cite this article as: Adel A. Ismail, Journal of Photochemistry & Photobiology, A: Chemistry, https://doi.org/10.1016/j.jphotochem.2020.113037 Available online 12 November 2020 1010-6030/© 2020 Elsevier B.V. All rights reserved. Pyrolysis conversion of metal organic frameworks to form uniform codoped C/N-Titania photocatalyst for H 2 production through simulated solar light Adel A. Ismail a, b, *, L.A. Al-Hajji a , M. Alsaidi a , B.N. Nunes c , D.W. Bahnemann c a Nanotechnologyand Advanced Materials Program, Energy & Building Research Center, Kuwait Institute for Scientifc Research (KISR), P.O. Box 24885, Safat, 13109, Kuwait b Advanced Materials Department, Central Metallurgical R&D Institute, CMRDI, P.O. Box 87, Helwan, Cairo, 11421, Egypt c Institut für Technische Chemie, Leibniz Universit¨ at Hannover, Callinstrasse 3, D-30167, Hannover, Germany A R T I C L E INFO Keywords: NH 2 -MIL-125(Ti) Pyrolysis C/N-TiO 2 H 2 evolution Simulated solar light ABSTRACT In this contribution, C/N-TiO 2 photocatalyst has been synthesized employing the combustion approach of NH 2 - MIL-125(Ti) at 400 ◦ C in air for H 2 production through simulated solar light compared with either NH 2 -MIL-125 (Ti) or commercial P-25. TEM images show well defned shape TiO 2 nanocrystalline with 10 nm particles size. The obtained C/N-TiO 2 photocatalyst exhibited large surface area 1066 m 2 g 1 with high pore volume ~0.537 cm 3 g 1 and pores diameter ~1.3 nm. The yield of H 2 evolution over C-N/TiO 2 photocatalyst (339 H 2 mmol g 1 ) exhibited signifcantly compared with NH 2 -MIL-125(Ti) (5.7 H 2 mmol g 1 ) and P-25 TiO 2 (144.8 H 2 mmol g 1 ) photocatalyst. The yield of H 2 evolution over C/N-doped TiO 2 was boosted by 60 and 2.35 times after 6 h over NH 2 -MIL-125(Ti) and P-25 TiO 2 photocatalyst. The H 2 evolution rate of C/N-TiO 2 photocatalyst reached 33.3 mmol g -1 h -1 and it is greater 2.17 and 27.5 times than P-25 TiO 2 (15.3 mmol g -1 h 1 ) and NH 2 -MIL-125(Ti) (1.212 mmol g -1 h 1 ). The enhancement of photocatalytic effciency over C/N-TiO 2 photocatalyst was referred to its great mesoporosity, hierarchical structure and large surface area. The recycled C/N-TiO 2 photocatalyst showed signifcant durability through fve consecutive runs for 30 h illumination. The C/N-TiO 2 , synthesized from pyrolysis of NH 2 -MIL-125(Ti), is proposed as an outstanding material for H 2 evolution and potential photocatalysis application under simulated solar Light. 1. Introduction Photocatalytic H 2 evolution is an effcient and potential approach to save solar energy and it is considered one of the serious issues regarding the development of high and stable effective photocatalysts [1,2]. In the last four decades, numerous semiconductor materials have been con- structed for H 2 production upon exposure to UV and visible light illu- mination [3–5]. The effective charge separation and utilizing of visible light photocatalysts for H 2 evolution have been scarcely achieved. Doping of C, N, and S into TiO 2 was confrmed to be more suffcient than other dopants for promoting their photoactivity under visible light illumination owing to the impurity states are close the edge of TiO 2 valence band (VB). However, nonmetals use as recombination positions and do not present as carriers, they are certainly smaller than of metal cations doping [6–10]. C- or N- doped TiO 2 photocatalyst among all nonmetals has been proven to reveal outstanding photocatalytic performance under visible light illumination owing to C or N elements can effciently tight the bandgap energy of TiO 2 [6–10]. Metal-organic frameworks (MOFs) have attaching organic com- pound as linkers and inorganic secondary constructing units, for instance, clusters of metal ions with porous crystalline materials; they have been comprehensively employed for H 2 evolution as effcient visible light photocatalysts [11–27]. However, the photocatalytic per- formance of MOFs yet has suffered from intrinsic defects, for instance, low conductivity, low effciency, and fast charge recombination indi- cating to poor photocatalytic effciency compared to conventional inorganic semiconductor materials [27,28]. Thus, numerous scenarios were promoted to enhance the photoactivity of MOFs as active photo- catalysts. In this context, the combination of MOFs with dye sensitizers [13,14], metal oxides or sulfdes [22–24], and metal nanoparticles (NPs) [16–21] has been demonstrated to be effcient approaches for prohib- iting the electron-hole recombination and expediting the charge carriers * Corresponding author at: Nanotechnologyand Advanced Materials Program, Energy & Building Research Center, Kuwait Institute for Scientifc Research (KISR), P.O. Box 24885, Safat, 13109, Kuwait. E-mail address: aaismail@kisr.edu.kw (A.A. Ismail). Contents lists available at ScienceDirect Journal of Photochemistry & Photobiology, A: Chemistry journal homepage: www.elsevier.com/locate/jphotochem https://doi.org/10.1016/j.jphotochem.2020.113037 Received 1 August 2020; Received in revised form 6 November 2020; Accepted 8 November 2020