Front Matter -- Introduction / Zongyou Yin -- Emerging Nanomaterials for Electrochemical (EC) Energy Conversion. 2D-Materials-Free Heterostructures for EC Energy Conversion / Kamran Dastafkan, Chuan Zhao -- 2D-Materials-Based Heterostructures for EC Energy Conversion / Zhengqing Liu -- Superlattices for EC Energy Conversion / Hang Yin, Zongyou Yin -- Polymorphic Phase Engineered Structures (PPESs) for EC Energy Conversion / Nasir Uddin, Ziyang Lu, Zongyou Yin -- Rare-earth Nanomaterials for EC Energy Conversion / Tong Wu, Mingzi Sun, Bolong Huang, Yaping Du -- Emerging Nanomaterials for Photochemical (PC) Energy Conversion. 2D-Materials Free Heterostructures for photochemical Energy Conversion / Wei Chen, Guohua Jia -- Van der Waals Heterostructures in Photocatalytic Energy Conversion / Bikesh Gupta, Han Li, Julie Tournet, Hark H Tan, Chennupati Jagadish, Shaowen Cao, Siva K Karuturi -- Superlattices for PC Energy Conversion / Hang Yin, Zongyou Yin -- Polymorphic Phase Engineered Structures (PPESs) for PC Energy Conversion / Nasir Uddin, Ziyang Lu, Zongyou Yin -- Rare-earth Nanomaterials for PC Energy Conversion / Tong Wu, Mingzi Sun, Bolong Huang, Yaping Du -- Non-noble Plasmonic Enhancement (NNPE) for PC Energy Conversion / Chao Yang, Shaowen Cao -- Emerging Nanomaterials for Photoelectrochemical (PEC) Energy Conversion. 2D Materials-Free Heterostructures for PEC Energy Conversion / Wei Chen, Guohua Jia -- 2D-Materials-based Heterostructures for PEC Energy Conversion / Bikesh Gupta, Julie Tournet, Hark H Tan, Chennupati Jagadish, Siva K Karuturi -- Polymorphic Phase Engineered Structures (PPES) for PEC Energy Conversion / Nasir Uddin, Zongyou Yin -- Rare-earth Nanomaterials for PEC Energy Conversion / Tong Wu, Mingzi Sun, Bolong Huang, Yaping Du -- Non-Noble Plasmon Enhancement (NNPE) for PEC Energy Conversion / Sandra Saji, Zongyou Yin -- Emerging Nanomaterials for Photovoltaic (PV) Energy Conversion. 2D-Materials Free Heterostructures for Photovoltaic Energy Conversion / Wei Chen, Guohua Jia -- 2D-Materials-based Heterostructures for PV Energy Conversion / Chun H Mak, Jung-Ho Yun, Hoi Y Chung, Yun H Ng, Hsien-Yi Hsu -- Perovskite-Si Tandem Solar Cells / Disheng Yao, Hongxia Wang -- III-V Compound Semiconductor Nanowire Solar Cells / Ziyuan Li, Hark H Tan, Chennupati Jagadish, Lan Fu -- Rare-Earth Nanomaterials for PV Energy Conversion / Tong Wu, Mingzi Sun, Bolong Huang, Yaping Du -- Non-noble Plasmon Enhancement (NNPE) for PV Energy Conversion / Jung-Ho Yun, Chun Hong Mak, Hsien-Yi Hsu, Yun Hau Ng -- Clusters for Energy Conversion. Electrochemical Energy Conversion with Clusters / Zhengqing Liu, Sandra E Saji, Zongyou Yin -- Photochemical Energy Conversion with Clusters / Xiaoshan Zhang, Sandra E Saji, Zongyou Yin -- Photoelectrochemical Energy Conversion with Clusters / Kaili Liu, Zongyou Yin -- Single Atoms for Energy Conversion. Electrochemical Energy Conversion with Single Atoms / Peilong Lu, Sandra E Saji, Haitao Zhao, Zongyou Yin -- Photochemical Energy Conversion with Single Atoms / Haijiao Lu, Zongyou Yin -- Photoelectrochemical (PEC) Energy Conversion with Single Atoms / Mahmoud M Abdelnaby, Zongyou Yin -- Future Perspectives / Zongyou Yin.