oxygen evolution of BHx gradually i

oxygen evolution of BHx gradually increased, with the highest
oxygen evolution rate reaching 183.2 µmol h−1
g−1 for BH400,
which is almost twice that of pristine g-C3N4 (98.6 µmol h−1
g−1
).
However, with calcination temperature further increased up
to 450 and 500 °C, BHx (x = 450 and 500) shows photocata￾lytic activities much decreased and even lower than the pris￾tine g-C3N4. That is to say, the introduction of boron dopants
and nitrogen defects should be optimized to achieve an excel￾lent photocatalytic activity for oxygen evolution. With Co(OH)2
cocatalyst loaded onto BHx (see Experimental Section for
details in the Supporting Information), all the samples show
significant increase in photocatalytic activity (Figure 5d). Spe￾cifically, the oxygen evolution rate of BH400 was dramatically
increased to 561.2 µmol h−1
g−1
with an apparent quantum
yield of 3.7% at 380 nm, which is much higher than that of
most reported g-C3N4 (Table S5, Supporting Information).
The photocatalytic activities of the CN–B and CN–H were
thereafter investigated and compared with that of g-C3N4 and
BH400 in Figure 5e. It can be seen that respective introduc￾tion of boron dopants (CN–B) or nitrogen defects (CN–H)
into g-C3N4 can improve the photocatalytic activity for oxygen
evolution of g-C3N4 to a certain extent.