<?php 
$currentTerm = get_queried_object();
$children = get_term_children($currentTerm -> term_id, 'catalogs');
if($children): ?>
  <?php 
        $args = array(
          'taxonomy' => 'catalogs',
          'hide_empty' => 1,
          'depth' => 1,
          'parent' => get_queried_object()->term_id
        );
        $terms = get_terms( $args );
        $count = 1;
  ?>

  <?php foreach ($terms as $term): ?>

    <a href="<?php echo get_post_type_archive_link('catalog'); echo $term->slug ?>"><?php echo $term->name ?></a>
  <?php endforeach; ?>

  <?php else : ?>
	<?php  if ( have_posts() ) :  while (have_posts()) : the_post();?>
		<h2><?php the_title(); ?></h2>
	<?php endwhile;?>
	<?php endif;?>
<?php endif;?>