Strong Tribocatalytic Nitrogen Fixation of Graphite Carbon Nitride g-C3N4 through Harvesting Friction Energy

Abstract

Mechanical energy derived from friction is a kind of clean energy which is ubiquitous in nature. In this research, two-dimensional graphite carbon nitride (g-C3N4) is successfully applied to the conversion of nitrogen (N2) fixation through collecting the mechanical energy generated from the friction between a g-C3N4 catalyst and a stirring rod. At the stirring speed of 1000 r/min, the tribocatalytic ammonia radical (NH4+) generation rate of g-C3N4 can achieve 100.56 μmol·L−1·g−1·h−1 using methanol as a positive charge scavenger, which is 3.91 times higher than that without any scavengers. Meanwhile, ammonia is not generated without a catalyst or contact between the g-C3N4 catalyst and the stirring rod. The tribocatalytic effect originates from the friction between the g-C3N4 catalyst and the stirring rod which results in the charges transfer crossing the contact interface, then the positive and negative charges remain on the catalyst and the stirring rod respectively, which can further react with the substance dissolved in the reaction solution to achieve the conversion of N2 to ammonia. The effects of number and stirring speed of the rods on the performance of g-C3N4 tribocatalytic N2 fixation are further investigated. This excellent and efficient tribocatalysis can provide a potential avenue towards harvesting the mechanical energy in a natural environment.

Strongly enhanced piezocatalysis of BiFeO3/ZnO heterostructure nanomaterials

“…of the piezocatalytic dye decomposition ratio is the excessive ZnO content acting as the recombination center rather than as the charge separation role in the BiFeO 3 /ZnO heterostructures. 38,41,42 To compare the reaction kinetics of the BiFeO 3 /ZnO heterostructures in different ZnO contents, the pseudo first order kinetic equation is investigated in eqn (2): 43,44 ln…”

“…To compare the reaction kinetics of the BiFeO 3 /ZnO heterostructures in different ZnO contents, the pseudo first order kinetic equation is investigated in eqn (2): 43,44 …”

Remarkable Pyro-Catalysis of g-C3N4 Nanosheets for Dye Decoloration under Room-Temperature Cold–Hot Cycle Excitation

“…In future, there is hope of further enhancing the pyro-catalysis performance of the 2D organic g-C 3 N 4 catalyst through building a heterojunction structure to increase the separation of pyroelectrically induced positive and negative charges [ 44 , 45 , 46 , 47 ]. Besides the pyro-catalysis for harvesting environmental cold–hot thermal energy, the 2D organic g-C 3 N 4 nanosheet catalyst materials can be also designed to harvest mechanical energy to drive a chemical catalysis reaction [ 48 , 49 ]. The 2D organic g-C 3 N 4 catalyst nanomaterials have been reported as having an excellent piezocatalytic performance [ 48 ].…”

“…The 2D organic g-C 3 N 4 catalyst nanomaterials have been reported as having an excellent piezocatalytic performance [ 48 ]. In our previous report, we have also found that the 2D organic g-C 3 N 4 could exhibit a strong tribocatalytic performance for nitrogen fixation through harvesting environmental friction energy [ 49 ]. It has the potential to obtain the enhanced catalytic dye decoloration performance of the 2D organic g-C 3 N 4 nanosheet catalyst nanomaterials by harvesting both the environmental cold–hot temperature alternation thermal-energy and the ordinary mechanical friction energy and vibration energy on basis of the synergy of muti-catalysis in future [ 50 , 51 , 52 , 53 , 54 ].…”

Tribocatalysis mechanisms: electron transfer and transition

“…67,68 N 2 can be converted to NH 3 by stirring g-C 3 N 4 catalyst and methanol solution with a PTFE magnetic bar at 1000 rpm. 69 After the friction between g-C 3 N 4 and PTFE magnetic bar, PTFE gained electrons while g-C 3 N 4 lost electrons (Fig. 14c).…”