Synthesis methods, analysis of photocatalytic properties and technological features of the application of photo-catalytically active materials for environmental pollution degradation, in the composition of modern building materials, and in the processes of energy conversion are topics of the presented specialised collection. This book is the second part of the series "Photocatalysts" which contains articles published by Trans Tech Publications Ltd. in the last few years. The edition will be helpful and interesting to a broad audience of photocatalysis and environmental protection specialists.