Controlling Solar Hydrogen Production by Organizing Porphyrins

Abstract

In this study, a highly efficient photocatalytic H2 production system is developed by employing porphyrins as photocatalysts. Palladium and platinum tetracarboxyporphyrins (PdTCP and PtTCP) are adsorbed or coadsorbed onto TiO2 nanoparticles (NPs), which act as the electron transport medium and as a scaffold that promotes the self‐organization of the porphyrinoids. The self‐organization of PdTCP and PtTCP, forming H‐ and J‐aggregates, respectively, is the key element for H2 evolution, as in the absence of TiO2 NPs no catalytic activity is detected. Notably, J‐aggregated PtTCPs are more efficient for H2 production than H‐aggregated PdTCPs. In this approach, a single porphyrin, which self‐organizes onto TiO2 NPs, acts as the light harvester and simultaneously as the catalyst, whereas TiO2 serves as the electron transport medium. Importantly, the concurrent adsorption of PdTCP and PtTCP onto TiO2 NPs results in the most efficient catalytic system, giving a turnover number of 22,733 and 30.2 mmol(H2) g(cat)−1.

Electronic and energy level engineering of directly fused porphyrin-conjugated polymers – impact of the central metal cation

“…Therefore, porphyrin-based materials are highly attractive in artificial light-harvesting systems, 1,2 including photocatalytic and photoelectrochemical approaches towards hydrogen production from solar-assisted water splitting. [3][4][5] The features of porphyrins (e.g. optoelectronic and catalytic properties) can be further enhanced by assembling them into large p-conjugated systems, e.g.…”

Long-lived excited states of platinum(ii)-porphyrins for highly efficient photocatalytic hydrogen evolution

“…Recently, the research on photocatalytic hydrogen evolution (PHE) has been developed very fast for the production of H 2 as a clean energy and renewable fuel that would reduce the consumption of fossil fuels and alleviate the global warming crisis. 6 To date, various photocatalysts based on transition metal complexes, [7][8][9][10][11][12] porous materials, 3,[13][14][15][16] metal suldes/ oxides, [17][18][19] organic and inorganic hybrids, 11,[20][21][22][23][24][25] organic molecules, [26][27][28][29] and porphyrins 5,[30][31][32][33][34][35][36] have been demonstrated for efficient PHE. Among them porphyrins received much more attention for PHE due to their strong light absorption in the UVvisible region and easily tailorable photophysical and redox properties by integrating different aromatic chromophores to the porphyrin ring and inserting different metals in the porphyrin ring.…”

Spiky Cascade Biocatalysts as Peroxisome-Mimics for Ultrasound-Augmented Tumor Ablation

“…The conventional methods of cancer treatments, including surgery, radiotherapy, and chemotherapy, have several limitations, such as poor prognosis, severe side effects, and drug resistance. − Though emerging clinical ablation procedures have been gradually applied to cancer treatment, such as microwave ablation and radiofrequency ablation, the stubborn coagulative necrosis tissue, invasive increased risk of bleeding, and easy relapse make it necessary to find other more effective or novel cancer treatment strategies. − Ultrasound (US)-augmented tumor ablation with sono-catalysts has emerged as a promising therapeutic modality due to high tissue penetration, nonionizing performance, and low cost of US-based therapies. , Typically, the sono-catalysts activated by the US can induce tumor cell apoptosis or necrosis through generating reactive oxygen species (ROS), which can lead to DNA, lipids, and proteins damages and cause structural failures of tumor cells. − Though these sono-catalysts including organic porphyrins and inorganic TiO 2 nanoparticles have been widely developed for tumor therapies, their low ROS generation and treatment efficacies are still unsatisfactory. − Therefore, it is particularly important to develop novel biocatalysts with high-efficiency ROS generation for US-augmented ablation of tumors.…”