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Graphical abstract Highlights • A recrystallization-annealing strategy was developed to fabricate alkalinized g-C 3 N 4 and TiO 2 composite. • The C N bond was dissociated while C OH was formed. • Synergetic effect of adsorption and photocatalysis enhanced the degradation of methylene blue. Abstract This work reports the fabrication of alkalinized g-C 3 N 4 and its composite with TiO 2 via recrystallization-annealing strategy. The increased surface basicity boosted the fast adsorptive removal of methylene blue (MB) while the cooperated TiO 2 enhanced the degradation of adsorbed MB via photocatalysis. The synthesized materials were characterized by XPS, SEM, TEM, PXRD, BET surface area, FT-IR, EDX and TG analyses. TiO 2 nanoparticles were uniformly distributed in the framework of alkalinized g-C 3 N 4 which increased the surface area of g-C 3 N 4. Na was incorporated into g-C 3 N 4 via thermal treatment, and the bond between C and N was dissociated while that between C OH was formed. The alkaline and negatively charged surface of g-C 3 N 4 upon Na addition established a strong electrostatic interaction adsorption scenario with MB leading to higher adsorption efficiency of TiO 2 /Na-g-C 3 N 4 (90%) than pristine g-C 3 N 4 (80%). MB removal efficiency was further intensified (from 90% to 100% within 120 min) upon the sequential operation of adsorption followed by photocatalytic degradation over TiO 2 /Na-g-C 3 N 4 under visible light irradiation. This study can be deemed of potential applications for the removal of MB and similar dyes on industrial level using the newly synthesized TiO 2 /Na-g-C 3 N 4 and synergistic adsorption-photocatalytic oxidation approach. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel synthesis route for porous metal oxide at three length scales is proposed. • The UV/visible photocatalytic activity of porous TiO 2 is 2.1/6.3 times of P25. • It shows high capacity of 100 mA h/g at 5 C, far better than commercial TiO 2. Abstract A feasible route with a dual-templating method including both ice and SiO 2 hard templates to fabricate hierarchical porous TiO 2 with micro-, meso-, and macro-pores from inorganic/organic metal oxo cluster precursors is proposed. As-prepared TiO 2 shows high photocatalytic activity and excellent electrochemical performances. The current strategy can be applied to fabrication of a broad range of metal oxide materials for catalysis and energy related applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Titania oxide with a shrubby morphology was prepared on carbon cloth to trigger SERS "hotspots" with a high-density. • The structure-dependent SERS and photocatalysis performance were investigated for as-prepared CC/TiO 2 /Ag hybrid substrates. • An actual detection of quercetin in teas was achieved by the self-cleaning SERS substrate. Constructing of plasmonic substrate with the capability of detecting nutritional food quality will soon be emerged as the frontier research directions with broad prospects in surface-enhanced Raman scattering (SERS) technology ascribed to an improvement of living standards. Herein, a novel TiO 2 framework with a shrubby morphology was successfully constructed on carbon cloth (CC) matrix to trigger significantly enhanced electromagnetic "hotspots" after dense Ag network with numerous sharp corners and edges was formed by a photo-induced reduction. Particularly, the structure-dependent optical performance was investigated for these as-prepared CC/TiO 2 /Ag hybrid substrates, screening out an optimal one with an enhancement factor of 6.38 × 107. Regarding a prominent photocatalytic efficiency ascribed to the high electron-hole separation efficiency assisted by the CC matrix and Ag decoration, a recyclable SERS-based monitoring of quercetin (QR) was achieved in teas, demonstrating recovery values distributed from 88.9 % to 106.4 %. The strategy proposed here opened a new way to create high-density "hotspots" for multifunctional SERS substrates, which might play a crucial role in food quality monitoring applications. [ABSTRACT FROM AUTHOR]