Purpose-The purpose of this paper is to present a novel swarm intelligence optimizer-pigeoninspired optimization (PIO)-and describe how this algorithm was applied to solve air robot path planning problems. Design/methodology/approach-The formulation of threat resources and objective function in air robot path planning is given. The mathematical model and detailed implementation process of PIO is presented. Comparative experiments with standard differential evolution (DE) algorithm are also conducted. Findings-The feasibility, effectiveness and robustness of the proposed PIO algorithm are shown by a series of comparative experiments with standard DE algorithm. The computational results also show that the proposed PIO algorithm can effectively improve the convergence speed, and the superiority of global search is also verified in various cases. Originality/value-In this paper, the authors first presented a PIO algorithm. In this newly presented algorithm, map and compass operator model is presented based on magnetic field and sun, while landmark operator model is designed based on landmarks. The authors also applied this newly proposed PIO algorithm for solving air robot path planning problems.

Photocatalytic hydrogen production using semiconductors is identified as one of the most promising routes for sustainable energy; however, it is challenging to harvest the full solar spectrum in a particulate photocatalyst for high activity. Herein, a hierarchical hollow black TiO2/MoS2/CdS tandem heterojunction photocatalyst, which allows broad‐spectrum absorption, thus delivering enhanced hydrogen evolution performance is designed and synthesized. The MoS2 nanosheets not only function as a cost‐effective cocatalyst but also act as a bridge to connect two light‐harvesting semiconductors into a tandem heterojunction where the CdS nanoparticles and black TiO2 spheres absorb UV and visible light on both sides efficiently, coupling with the MoS2 cocatalyst into a particulate photocatalyst system. Consequently, the photocatalytic hydrogen rate of the black TiO2/MoS2/CdS tandem heterojunction is as high as 179 µmol h−1 per 20 mg photocatalyst under visible‐light irradiation, which is almost 3 times higher than that of black TiO2/MoS2 heterojunctions (57.2 µmol h−1). Most importantly, the stability of CdS nanoparticles in the black TiO2/MoS2/CdS tandem heterojunction is greatly improved compared to MoS2/CdS because of the formation of tandem heterojunctions and the strong UV‐absorbing effect of black TiO2. Such a tandem architectural design provides new ways for synthesizing particulate photocatalysts with high efficiencies.

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