Photocatalytic Hydrogen Generation Enabled by Nanostructured TiO ₂ Materials

Oxygen Reduction Reaction in the Field of Water Environment for Application of Nanomaterials

“…As the world energy crisis intensifies and pollution problems deteriorate, there is an urgent need to develop renewable energy and systems with high energy conversion efficiency to ensure sustainable human development [6]. As the most promising clean energy, solar energy has attracted widespread attention over the years [74]. In recent years, through the use of solar photocatalytic hydrogen production and oxygen production, there has been a substantial increase.…”

“…The xylylene blue nano-dye can significantly improve the electron transfer kinetics. However, in terms of resource utilization, the scarcity of precious metal sources and high acquisition costs have seriously hindered its expansion and application in the field of electro-chemicals [74]. Therefore, how to stabilize the efficiency and ensure a relatively lower cost of catalysts production and regeneration is vital going forward.…”

“…TiO 2 Nanosheets Photocatalytic hydrogen production [17,74] CuOx-TiO 2 Solar hydrolysis [80] Ni-Zn/TiO 2 (9:1) Photocatalytic hydrogen production [88] TiO 2 /WO 3 /Au/MWCNT Photocatalytic hydrogen production [82] CdS-CTF-1 Photocatalytic hydrogen production [77] 0D ZAIS CQD and 2D MoS 2 Photocatalytic hydrogen production [89] MoS 2 /Graphene Electrocatalytic oxygen production [50] CoNiO x /rGO Electrocatalytic oxygen production [20] FeNi 2 Se 4 -NrGO Bifunctional catalyst for OER and ORR [80] MoS 2 /N-RGO-180 Electrocatalytic oxygen production [90] Fe(Ni)-MOF Electrocatalytic oxygen production [33] Manganese copper sulfide (MCS) Photocatalytic and electrocatalytic hydrolysis [39] PRh/ZnO/Ni/Pt Methanol oxidation [68] With the vigorous research and development of new materials, nanomaterials have advantages in water pollution control, such as the presence of surface effects, which increases their specific surface area [91,92]. In addition, large and enhanced surface activity and small size effects can effectively enhance their adsorption capacity [3,30,93].…”

“…However, it requires too much energy to overcome the activation energy of the anode side oxygen release reaction. Therefore, chemical hydrogen storage materials with high hydrogen storage capacity and easy dehydrogenation have also attracted people's attention, such as hydrazine hydrate and ammonia boron [74], hydrocarbons (formic acid, methanol [70], etc. ), and urea [75].…”

“…According to the standard Gibbs free energy change relationship, ΔG = +237.2 kJ mol −1 (Equation (6)). Therefore, additional energy must be provided to overcome the positive change in the freedom of Gibbs during the decomposition process [ 74 ]. At present, there are two main ways of energy source: (1) light catalytic hydrolysis, which is mainly limited by the width of the energy gap band mentioned above, and the absorption range of solar light is extremely narrow (mostly absorbing only 3–4% ultraviolet rays); and (2) electrocatalytic hydrolysis (OER) under the standard atmospheric pressure 1.23 V, and the theoretical electrode power of cathode hydrogen analysis reaction is 0.00 V. This indicates that the anode needs additional energy to make the hydrolysis response proceed smoothly [ 75 ].…”