“…flows through. 6,[51][52][53][54][55] Besides, nickel oxide can be synthesized via several methods, including the chemical deposition method, 56,57 solution growth technique, 58 SILAR method, 59 thermal decomposition, combustion method, 60 sonochemical, electrolysis, 61 solid-state reaction, 62 chemical precipitation and chemical combustion methods, 51 pulsed laser deposition 52 amongst others. 53,54 Before delving into the details of our present review, it is important to mention several interesting works on NiO, which relates to its application as HTM.…”